Derryn Hinch’s fledgling Victorian party has lost a rookie MP before she was even sworn into state Parliament.

But the day before the trio was due to be sworn in, Catherine Cumming has announced she will quit the party and sit as an independent.

The former western suburbs councillor and two-time mayor of Maribrynong had a falling-out with the party that appears to have been brewing for weeks.

She told the ABC she was quitting because she did not win the vote to lead the party, despite having more than two decades of political experience in local government.

She also said she did not want to be associated with the so-called “preference whisperer”, Glenn Druery, who is the subject of a complaint to police about his dealings with political parties and the harvesting of votes.

“I realised I can’t work with Glenn Druery,” she said.

She also said she felt sidelined by the party and had to fight with them during the campaign to get her face on election material.

But Senator Hinch said Ms Cumming was disendorsed because of childish behaviour during the leadership ballot she lost to Stuart Grimley.

“If you don’t elect me as leader, I will throw my toys out of the pram. I will quit,” Senator Hinch claims she said.

“She was happy to have banners featuring my face, and the Justice Party logo, all over Footscray, to get in,” Senator Hinch said in a statement.

“I call it the Cory Bernardi syndrome. He was elected as a Liberal and then betrayed his party.”

Senator Hinch channelled a football legend to describe his disappointment.

“As Ron Barassi used to say: ‘There is no ‘I’ in team’,” he said.

Senator Hinch’s party was the largest bloc on the Upper House’s crossbench of 11 MPs.

The Andrews Government has 18 out of 40 votes in the Upper House, and will need three votes from the crossbench to pass any legislation opposed by the Coalition.

–ABC