A Federal Labor frontbencher has called on Foreign Minister Julie Bishop to apologise for accusing former prime minister Julia Gillard of breaking the law.

The counsel assisting the Royal Commission into Trade Union Governance and Corruption, Jeremy Stoljar SC, has recommended the former Labor leader be cleared of any crime over her involvement in the setting up of an Australian Workers Union (AWU) slush fund in the 1990s.

However, the summary of submissions to the commission released on Friday said AWU officials Bruce Wilson and Ralph Blewitt ran a "sham" slush fund, of which the sole purpose was to receive money fraudulently from the Perth construction company Thiess Contractors.

Mr Wilson fronted the commission in September and admitted that his "association" sent false invoices to Thiess for a whole year in 1992.

Although it found Ms Gillard's professional conduct to be "questionable", the document said the former prime minister did not commit any crime and was not aware of any criminality on the part of other union officials.

It was noted by Mr Stoljar that had Ms Gillard taken a more rigorous approach, it might have been more difficult for the pair to have behaved as they did.

The interim report of the commission has not been released, but the recommendation has come from a summary of evidence so far.

Ms Bishop had previously suggested that the former prime minister had benefited from siphoned-off funds.

Labor frontbencher Andrew Leigh said members of the Coalition who accused Ms Gillard of wrongdoing in the media and in parliament should now say sorry.

"I think it might be appropriate for someone like Julie Bishop, who had accused Julia Gillard of criminality, now to issue a formal apology," Dr Leigh said.

Coalition frontbencher Josh Frydenberg stressed that the released report is only preliminary.

"I've never thought this royal commission was about Julia Gillard, it's a much more systemic problem within the union movement," Mr Frydenberg said.

On Saturday, Ms Gillard, who has always denied any wrongdoing, released a brief statement acknowledging the recommendation.

"Ms Gillard notes that the submission made by counsel assisting the Royal Commission into Trade Union [Governance and] Corruption states that she did not commit any crime and she was not aware of any criminality by any other person," the statement said.

"In relation to the other matters detailed in the submission relevant to Ms Gillard, her counsel will make submissions at the appropriate point."

New South Wales Opposition Leader John Robertson said the lack of any adverse finding about Ms Gillard is a demonstration that the royal commission is a witch hunt.

"Lawyers often have questions raised about their behaviour, and I would suggest that there are processes within the legal fraternity that should easily deal with those matters," Mr Robertson said.

"The former prime minister was treated appallingly in the way she was pursed on this matter.

"She has been cleared, I think that's a good thing for her and I'd like to think that she will be able to get on with her life."