The royal commission into union corruption has concluded that Julia Gillard suffered a "lapse of professional judgment" by providing legal representation to her former boyfriend.
The interim report of the commission said there was "in one sense" a conflict of interest in Ms Gillard representing Australian Workers Union official Bruce Wilson.
Mr Wilson - who's no longer a union official - was a major client of law firm Slater and Gordon where Ms Gillard worked in the 1990s.
The commission was told this perhaps represented a "lapse in professional judgment" on Ms Gillard's part.
"To that extent the criticism is justified," the report states.
The commission also questioned Ms Gillard's credibility regarding a 20-year-old allegation that the AWU paid for her home renovations in the 1990s.
The report states Ms Gillard was "very well versed" in the evidence given to the commission by other witnesses, given she took the stand last.
She demonstrated "occasional evasiveness, or non-responsiveness, or irritability," the report stated, but was generally what judges call "a very good witness".
It also noted she'd had 20 years to mull over the case and remained determined to vindicate her position.
"All this - her intense degree of preparation, her familiarity with the materials, her acuteness, her powerful instinct for self-preservation - made it hard to judge her credibility," the report states.
Federal Employment Minister Eric Abetz said the question of whether Ms Gillard had done anything wrong was "very broad".
The commission had made observations about her evidence, but unlike Mr Wilson and another former trade union official, Ralph Blewitt, she had not been referred to state prosecutors.
"The important thing is that those that have done wrong, criminal activities, according to the Royal Commissioner, should be brought to justice," he told reporters in Canberra on Friday.
"Ms Gillard does not fall into that category."
