Multiple senior Liberal Party sources have spoken to STPL News claiming Mornington Peninsula Shire Mayor Anthony Marsh joined the Liberal Party within the past week and intends to nominate for Liberal preselection in Nepean, following Sam Groth’s announced resignation from Victorian Parliament.
Groth’s departure is expected to trigger a by-election in the Mornington Peninsula electorate once parliamentary processes are finalised.
Sources warn of internal backlash
Several party insiders told STPL News the prospect of a sitting council mayor entering the contest as a recent party member would not be welcomed by sections of the approximately 200-strong local Nepean membership of the Liberal Party.
One senior Liberal member, speaking on condition of anonymity, said it “will not sit well” locally and could be seen as “giving Labor a free kick” at the by-election.
The same source said Marsh was “too risky” and “carries too much baggage”, pointing to the state-appointed municipal monitors at Mornington Peninsula Shire Council and what they described as the prospect of the council being put under administration.
STPL News is reporting these comments as the views of sources. STPL News has not independently verified the timing of any party membership change. Political parties typically do not publicly confirm individual membership details.
State-appointed monitors and governance scrutiny
In late 2025, the Victorian Government appointed municipal monitors to Mornington Peninsula Shire Council as part of an oversight arrangement focused on governance and councillor conduct.
The appointment of monitors has become a political flashpoint locally, with critics arguing it reflects ongoing instability at the council and others arguing it provides a pathway to improved governance.
Context: Marsh previously ruled out a tilt
Marsh is the current Mayor of Mornington Peninsula Shire Council.
In prior public reporting, Marsh was quoted ruling out a run for Nepean and stating he was not a Liberal Party member at that time.
If confirmed, the claims now being put to STPL News would represent a significant change from that earlier position.
Comparisons raised by sources
Sources who contacted STPL News compared the prospect of Marsh entering parliament as a recent party member to past examples where Liberal MPs later broke with the party, naming Geoff Shaw and Julia Banks.
STPL News is reporting these comparisons as the views of sources, not as a prediction about any potential candidate.
Nepean by-election
Nepean has historically been held by the Liberal Party and is expected to be closely contested at the upcoming by-election.
The timing of the poll will be determined once Groth’s resignation takes effect and formal processes are completed.
Right of reply
STPL News contacted Mayor Anthony Marsh seeking comment on:
- whether he has recently joined the Liberal Party
- whether he intends to nominate for Liberal preselection in Nepean
This story will be updated if responses are received.
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