Cause of by-election
Sitting Liberal MP Sam Groth resigned from parliament on 4 February 2026, after previously flagging his intention to retire at the November general election in late 2025, and then stepping down as the party’s deputy leader in January 2026.
Margin – LIB 6.4%
Incumbent MP
Sam Groth, since 2022.
Geography
Mornington Peninsula. Nepean covers the southernmost part of Mornington Peninsula, including Point Nepean.
History
Nepean was created in 2002, replacing the abolished seat of Dromana, which had always been held by the Liberal Party since its creation in 1967.
Dromana was won in 1996 by Martin Dixon. He was re-elected in 1999. In 2002 he ran for Nepean, and held the seat until his retirement in 2018.
Labor candidate Chris Brayne won Nepean in 2018 after a large 8.5% swing.
Brayne lost in 2022 to Liberal candidate Sam Groth, who gained a 7.1% swing after preferences.
Assessment
On a two-party-preferred basis, this seat would probably be safe for the Liberal Party, and it is unlikely that Labor will contest the by-election. It will be interesting to see how One Nation performs at a time when national polls have them polling more strongly than ever before.
| Candidate | Party | Votes | % | Swing |
| Sam Groth | Liberal | 19,614 | 48.1 | +4.0 |
| Chris Brayne | Labor | 13,308 | 32.6 | -5.3 |
| Esther Gleixner | Greens | 3,576 | 8.8 | -2.2 |
| Hank Leine | Freedom Party | 980 | 2.4 | +2.4 |
| Pamela Engelander | Animal Justice | 720 | 1.8 | +1.8 |
| Janny Dijkman | Family First | 638 | 1.6 | +1.6 |
| Jay Miller | Companions and Pets | 526 | 1.3 | +1.3 |
| Elizabeth Woolcock | Independent | 495 | 1.2 | +1.2 |
| Charelle Ainslie | Independent | 449 | 1.1 | +1.1 |
| Cynthia Skruzny | Democratic Labour | 369 | 0.9 | +0.9 |
| Steve Anger | Independent | 91 | 0.2 | +0.2 |
| Informal | 2,753 | 6.3 |
2022 two-party-preferred result
| Candidate | Party | Votes | % | Swing |
| Sam Groth | Liberal | 22,986 | 56.4 | +7.1 |
| Chris Brayne | Labor | 17,780 | 43.6 | -7.1 |
Booths have been divided into three areas: east, south and west.
The Liberal Party won a majority of the two-party-preferred vote in two out of three areas, with 51.4% in the east and 57.2% in the west. Labor won 51.1% in the south. The Liberal Party also won large majorities on the special votes.
| Voter group | LIB 2PP | Total votes | % of votes |
| East | 51.4 | 4,737 | 11.6 |
| West | 57.2 | 3,247 | 7.9 |
| South | 48.9 | 1,990 | 4.9 |
| Pre-poll | 56.8 | 24,056 | 58.8 |
| Other votes | 61.8 | 6,902 | 16.9 |
Election results in Nepean at the 2022 Victorian state election
Toggle between two-party-preferred votes and primary votes for the Liberal Party and Labor.
With leader ship rumours I think it will be Sam Groth replacing Brad Battin as leader.
I’ve also read about the leadership rumblings. I think Sam Groth or Jess Wilson or both will put their hats in the ring if the role is open. Since they are first-termers, they might struggle to win trust within the party and the electorate more broadly.
Would this be a teal seat based on federal election numbers from Flinders?
I doubt a Sam growth jess Wilson combo will eventuate being first termers they won’t have the numbers. But I think hpjes Wilson could possibly get the deputy role.
@Votante – I’ll do a map and try to get a calculation of the booths from Flinders, but my current observation is that Flinders would be a marginal teal seat.
The numbers I got for Polling Day + Rosebud PPVC
15329 LIB (48.5%)
16227 IND (51.5%)
Adding in a calculated amount of postals which split 61-39 to the Liberals in Flinders altogether, and then calculating an average amount of postals that would projected to have been cast in the electorate:
20664 LIB (51.3%)
19637 IND (48.7%)
Liberals would likely win this seat.
James – that’s interesting to see. At first glance, I thought that the independent would’ve won on Nepean’s boundaries. My guess is that there were more postal voters in Portsea and Sorrento due to the population of retirees and the distance away from the PPVC.
Sam Groth seems to be a little bit accident prone with spending tax payers money being misused, in most circumstances this would cost an mp their job but given the Liberal parties other issues it seems to have gone unnoticed. If Sam Groth I would be careful as the margin here is rubbery and this seat can swing.
@ SpaceFish
I still dont think this is a seat Labor will target. It has a very High median age and wealthy not Labor’s typical demographic. In Hindsight Labor probably wished it won Croydon in 2018 than Nepean.
Sam Groth has announced his retirement from politics after one term, citing pressure on his family including from his own party.
I was surprised to see this however this will help Jess Wilson to fight off a potential leadership challenge from Sam Groth. I suspect in days, weeks and possible months more will come to light which might be damaging as well but only time will tell.
This seat isn’t under threat, votes about 8-15% to the right of the state depending on the candidate and is only line-ball in landslide years such as 2002 or 2018.
I have been wondering about Groth’s motivations here – seen a few takes but nothing quite stands out to me yet, I think there are a few possibilities…
1. His personal leadership ambitions have been scuppered by the deposing of his key ally Brad Battin.
2. He actually is one of the more honest and genuine actors in the space and couldn’t stand the white-anting and pressure applied from the Crozier types who leaked gossip to the media and tried to hang him out to dry over the expenses thing
3. He is in fact hiding skeletons/scandals and has been asked to stand aside and announce it during a quiet summer period
4. It’s a tough job and not everyone is up to it, I doubt I would be…
I’m not 100% sure but I think Groth only joined the Liberal party in opposition to Dan Andrews and lockdowns. Was he involved in politics at all prior to that?
Perhaps he has just realised, after just getting into it, that it’s not for him.
I am also surprised by Sam Groth’s retirement announcement. He was seen as a rising star and he is leaving after just one term.
He cited party pressure which makes me wonder about the internal party culture. He had a bitter feud with Herald Sun for some time.
The Liberals should retain this seat even without Groth’s profile and name recognition.
There could be a teal challenger given how close they were in Mornington in 2022 and in Flinders (in the Nepean part) at the 2025 fed election. I wouldn’t put my money on a teal win though.
@ Votante
Like Maxim correctly said this generally a blue ribbon Liberal seat and only falls at landslide elections like 2002/2018 votes about 8-15% to the right of the state. Even without Sam Groth i expect this seat to have a higher than Average swing 8-10% possible so if Libs get 52% TPP statewide i think a 17% margin is realistic. This seat is older and Whiter than average. As mentioned above in hindsight Labor probably wished it won Croydon instead as it is more reflective of middle Australia.
@Nimalan, Nepean was a surprise Labor win in 2018. The now former Labor MP was a 25 year old in 2018. Labor was unlikely to hold onto it for more than a term. Hawthorn was another surprise win. Labor did better than expected. I reckon Labor would’ve won an inner metro seat (Brighton, Caulfield) or an eastern suburbs seat (Croydon) if they’d planned and campaigned.
With Labor on the nose in the state in 2026, a teal (if one were to run) would likely produce a closer result than a Labor challenger would.
Agree Votante
I remember just before 2018 eleciton, it was said Labor’s target for pick ups were limited to Bass, South Barwon, Ripon, Burwood and Morwell. If we compare 2018 to 2002
1. Labor did much better in the Super Rich seats like Hawthorn, Brighton, Caulfield. I would say Turnbull ousted only 2 months earlier played a role
2. Labor did not do as well in Outer East Bayswater(still won but very narrow despite better boundaries for Labor than 2002), Ferntree Gully, Evelyn, Forest Hil
3. 2022 was mostly Sophomore surgers which is why Bayswater etc had big swings
Well, it’s confirmed – going to a byelection! Sam Groth to resign immediately.
Terrible timing for the Liberals. No doubt Labor will just sit this one out, probably leave the Liberals to contest it against a wide field of independents, having to spend resources & money only months before the general election.
Yep i think Labor should sit this one out, Maybe a Teal can run such as Ben Small
This is not a seat that Labor will expect to hold long term it is full of old rich white people.
Yeah Labor have only won the seat twice in 40 years (including the 2018 landslide).
This isn’t a seat they can win outside of a huge landslide year at peak, which is absolutely not the case at the moment, so they gain nothing from contesting the byelection. They have enough seats to defend in November that they’ll need to save up their resources for.
You’d think Ben Smith would be considering a run? If he can get funding behind him again he’d be a decent chance. Could be worth a deeper look into Flinder25 booth results compared to Nepean?
Looking at the Flinders 2025 booth results over on Poll Bludger, the Libs seem to average between roughly a -8 and -10 on 2CP vs Ben Smith compared to the equivalent booths vs Labor at the 2022 state election.
I reckon the IND would have won Nepean by around a 1-2% margin on the overlapping federal result.
That said, the VIC Libs I think will almost certainly do better than the federal Libs did last year; but if the Ben Smith runs and the Liberals look at that, it would force them to actually put effort & resources into defending it.