Labor leader Bill Shorten wants to fast-track giving evidence on his action at the Australian Workers Union (AWU), while Prime Minister Tony Abbott seizes the chance to criticise.

The Prime Minister says the Labor Party is in crisis over the royal commission into union corruption hearings.

Mr Shorten is on the list to give evidence about his time at the Victorian and federal branches of the Australian Workers Union (AWU), and wants to end the political muck-raking by moving his appearance forward to July 8.

Fairfax Media reports say Shorten’s ex-wife Deborah Beale has also been called to talk about some of her share dealings when she was married to Mr Shorten.

The Prime Minister used an address to the New South Wales Liberal conference in Sydney on the weekend to accuse union leaders of failing of their members.

“We know the focus has been on a particular union and on a particular union leader over the last week or so,” Mr Abbott said.

“But this is a crisis for the Labor Party more generally and what it shows is, as far as modern Labor is concerned, it isn't any more about the workers and their rights, it's about the union bosses and their privileges.

“What could be more shameful, what could be more embarrassing for someone who has a sacred trust to represent the workers of Australia, than to put himself or herself ahead of the interest whose job it is for them to represent, and yet that's what's happened.”

Labor MPs say the inquiry is just a politically motivated attempt to tear down the Opposition Leader.

“This is a very, very expensive witch hunt. It's not about improving the safety of workers in particular industries,” Labor frontbencher Matt Thistlethwaite told Sky News.

“It's not about improving the efficacy of the way our workplace relations system works.

“It's all about trying to damage the reputation of Bill Shorten.”

Mr Shorten is not responding to specific questions about payments that companies made to the AWU while he was its state and federal leader.

He did however suggest in an interview with the ABC that it was “entirely possible” construction companies paid union fees for workers during his tenure as a union leader.

“I don't have all of the detail of all of the claims being put to me,” Mr Shorten said.

Mr Shorten also defended a 2005 deal with Thiess John Holland, the builder of Melbourne's Eastlink toll road, wherein the company paid the AWU $300,000 as part of an enterprise agreement.

“I sat down and negotiated the best pay rates that civil construction workers had ever earned in Australia,” Shorten said.

“The job finished ahead of time which saved the taxpayer money... and it changed the model of construction, civil projects in Victoria.

“What we've been attacked for - Thiess John Holland paid for training of our delegates, paid for health and safety - this is not unusual in the construction industry.”