Tens of thousands of Victorian voters may be forced to the polls before the November state election after a veteran government MP quit parliament, fuming about "betrayal".

Government lower house whip Craig Langdon cited family reasons for his resignation on Wednesday, but pointed to disloyalty in Labor ranks.

He lost Labor preselection for the seat of Ivanhoe in July to Banyule councillor, Anthony Carbines.

"Notwithstanding my family and personal reasons for resigning, it has become increasingly difficult for me to participate in parliament given a number of my colleagues undertook offensive acts of disloyalty and betrayal," Mr Langdon said in a statement.

"When government ministers and other MPs participate and propagate the demise of longstanding, loyal and dedicated members it can cause harm to the party and government.

"This becomes evident in the recent federal election."

Mr Langdon's resignation raises the prospect of a by-election before the November 27 state election.

A by-election would cost about $350,000, a Victorian Electoral Commission spokeswoman said.

Under the Electoral Act, lower house Speaker Jenny Lindell must issue a writ for a by-election within one month of a seat becoming vacant.

A by-election could be held as early as AFL Grand Final day but the more likely date would be a Saturday in October.

Comment was being sought from Ms Lindell.

Premier John Brumby said Ms Lindell would need to consider whether a by-election would be in the best interests of Ivanhoe voters and democracy in Victoria.

"(She would need to consider) whether the people of Ivanhoe, whether the people of Victoria have had enough elections," he told reporters.

Mr Brumby said he only learnt of Mr Langdon's plans on Wednesday.

He described him as a solid MP.

"I don't know the reasons why he has resigned. There are always a range of complex reasons that people take into account - sometimes personal, sometimes political," the premier said.

The 53-year-old MP was elected as the Member for Ivanhoe in 1996.

Local Leader press reported Mr Langdon wrote to constituents, angry that Education Minister Bronwyn Pike had not responded to his questions about funding for Heidelberg West's education regeneration project.

Mr Langdon's daughter Kate defended her father's decision to quit.

"He's not been disloyal as such, he just couldn't go on," she told ABC Radio.

"It was just too hard - too hard to go into parliament and feel like ... he wasn't being trusted, and he didn't trust them."

Labor holds Ivanhoe by around 10.5 per cent.

Opposition scrutiny of government spokesman David Davis said Mr Langdon's resignation was a damaging blow for Mr Brumby.

"It's a clear slap in the face for John Brumby," he told reporters.

"Craig Langdon has been betrayed by the disloyalty of John Brumby's faceless factional men who run the Labor Party."

http://news.ninemsn.com.au/national/7950920/vic-mp-quits-parliament-months-from-...

mozzaok - don't comment or delete here plse, I don;t trust you.

the lefty loonies have shown their bullying ways here and in the govt.

they can't run a choko vine over a outhouse