Taxpayers will be on the hook for millions of dollars to run a by-election triggered by a once-rising Liberal star quitting state parliament.
Victorian MP Sam Groth announced in early January he would stand down as the party's deputy leader and not recontest his Mornington Peninsula seat of Nepean at the state election in November.
The former tennis ace has since decided to pull the pin next week to pursue "other opportunities", triggering a by-election.
In a statement, Mr Groth wished Opposition Leader Jess Wilson and the party the "very best" for the November election.
"Most importantly, I thank my family, my wife Britt and our twin boys, for their unwavering love and support," he said.
Mr Groth was not in Victorian parliament's lower house for question time on Wednesday afternoon, with Premier Jacinta Allan making fun of his desertion.
Ms Wilson, who replaced Brad Battin as state Liberal leader in a snap coup in November, said she spoke to Mr Groth on Tuesday and did not try to change his mind.
"Not at all," she said.
"I've spoken to Sam many times over the last few weeks ... this is a decision that Sam's taken in the best interests of his family."
Mr Groth previously revealed party infighting and public pressure on his family had become unbearable.
The 38-year-old and his wife settled legal action in November with Melbourne's Herald Sun newspaper over articles relating to when the pair began their relationship.
During the court process, it was revealed a Liberal MP had contacted the outlet with a "piece of gossip".
Liberal stalwart David Southwick easily won a vote over backbencher Chris Crewther to replace Mr Groth as deputy leader at a recent meeting.
Outside, Mr Groth refused to rule out leaving politics for a better job offer but insisted his intention was to serve out the remainder of his term.
"As I stand here right now, there is a zero per cent chance of me causing a by-election in Nepean," he said on January 28.
Mr Groth's life in politics followed a tennis career that included a world record fastest serve in 2012 and a career-high ATP singles ranking of 53 in 2015.
The former Davis Cup representative reclaimed the then ultra-marginal seat from Labor in 2022 on a margin of more than six per cent.
His impending resignation means Nepean voters will face the polls twice in 2026, with taxpayers to foot the extra bill for conducting the by-election.
Victoria's by-elections for the seats of Prahran and Werribee a year ago collectively cost $4.22 million.
Deputy Premier Ben Carroll would not be drawn on whether Labor should run a candidate in the Nepean by-election, saying the decision rests with the party's head office.
"Every part of this state, we fight hard for," he said.
The Victorian Liberals have been in opposition for all but four years this century and will need to net 16 seats to form majority government in November.
