LABOR faces a fight to hold the state seat of Melbourne after former minister Bronwyn Pike quit politics.
Ms Pike's resignation opens a path for the Greens to mount a major push to win the inner-city electorate, which would be the party's first lower house seat in the Victorian Parliament.
Ms Pike - Victoria's longest serving female minister - ended her 12-year career in politics yesterday, saying the ALP needed a chance to renew as it pushed for a return to power. ''Obviously byelections are challenging times for all parties … but I think this party is very committed to renewing itself and building for the future, and so this is an opportunity for that to happen,'' she said.
Ms Pike, who served as health and education minister, said signing off on the new Royal Children's Hospital was one of her proudest achievements.
Several senior Labor MPs expressed disgust at Ms Pike's resignation, with one saying that unlike Rob Hulls, who quit in January after a health scare, it appeared she did not have a legitimate reason. Another said if the Liberal Party did not run a candidate it would be incredibly difficult to retain Melbourne.
Author and academic Neil Cole - who held the seat of Melbourne for Labor before being ousted by Ms Pike in a 1999 preselection battle - said ''for those of us living in the area all our lives it is very disappointing''.
''She has never been a great Labor Party person and she is leaving at the most inopportune time and handing the seat over to the Greens,'' he said.
But several ALP groups, including the Victorian Labor Women's Network and the Labor Environment Action Network, took to Twitter to praise her legacy.
Opposition leader Daniel Andrews conceded holding the seat would be a challenge but said he was confident it would happen with a strong local candidate and campaign.
Victorian Greens leader Greg Barber said if the minor party won the seat in ''this finely balanced Parliament'' it would make a real difference to Victorian politics, similar to the impact of federal Greens MP for Melbourne Adam Bandt on the national stage.
In 2010 Ms Pike won Melbourne with an increased margin of 6 per cent off the back of a Liberal decision not to preference the Greens.
The Age understands it is unlikely the Liberals will field a candidate in the byelection, but it has not been ruled out.
Liberal Party state director Damien Mantach said the party was ''considering its options'' but added ''the Labor Party has held the seat since 1955''.
Labor sources said Jennifer Kanis, a Melbourne City councillor and senior associate at law firm Holding Redlich, -was frontrunner to be the ALP candidate.