By KIRSTEN LAWSON

Labor Leader Simon Crean attacked the left-wing unions threatening to sever their ties with the party as backward-looking yesterday.

But the renegade unionist at the centre of the row, Dean Mighell, said he had been inundated with calls of support after he quit Labor to join the Greens.

Mr Mighell and another unionist who left the party, Peter Marshall of the United Firefighters Union, are pushing for their unions to disaffiliate with Labor, and the powerful Manufacturing Workers Union is considering doing the same.

But Mr Crean said he was serious about "modernising" the party to appeal to a wider cross-section of the community.

"The nature of the workplace has changed and we've got to understand it and we've got to embrace it," he said.

"I'm prepared to be inclusive and consultative about the direction I want to take that change, and I would hope that people would be prepared to sit down and have those discussions before they jump to their own judgments."

Mr Mighell and other left-wing Victorian unionists have considered setting up their own party described by Mr Mighell as a "real labour party, or the old Labor Party reinvented". He had received much support yesterday, including people saying "can I have an application form", but was not pursuing a separate party at this stage.

"The messages of support have been unreal," he said. "Absolutely amazing. I think if there's something that Labor needs to take from this it's there's a lot of true believers out there, traditional Labor people, and it seems to have struck a real chord with them.

"If Labor ignores the messages if they fail to understand that, their options of holding or winning government are going to be pretty minimal."

The Victorian Textile Clothing and Footwear Union is believed to be one of those considering cutting ties with Labor.

But its federal secretary Tony Woolgar said while he had concerns about the party and textile workers had suffered as much if not more under Labor governments as Liberal, he would not resign.

"I've certainly got concerns about the direction in which they're going. I wouldn't like to see the Labor Party forget its roots. It's a party that was developed from the trade-union movement and I believe they should remember that," he said.

"[But] I take the view that I think you can do more from the inside than you can on the outside."

Front-bench MP Lindsay Tanner called for an overhaul of the party, saying too many MPs came from the union movement, branch stacking was rife and grassroots membership was "profoundly unappealing" for people who did not have political ambitions.

"The number of MPs who could be described as labour-movement professionals has increased substantially," he said. "We need to make a collective effort to increase the diversity background in the Labor Caucus."

Mr Crean said he, too, wanted to improve the quality of candidates, be more "inclusive" in developing policy, broaden membership and extend its relationship with non-union groups.

Labor's president, Greg Sword, has appealed to Mr Mighell to reconsider and warned that those quitting the party risked losing political influence.