Julia Gillard’s “questionable” conduct highlighted in a unions inquiry justifies the coalition’s pursuit of the former prime minister during her term in office, Attorney-General George Brandis says.

The lawyer leading inquiries for the trade unions royal commission has concluded Ms Gillard did not know about alleged criminal activity by her former partner, union boss Bruce Wilson, but did receive money from him.

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However, Jeremy Stoljar SC found in written submissions that aspects of Ms Gillard’s professional conduct as a solicitor “appear questionable”.

Senator Brandis said it was a “very serious” finding.

“I do think that the conclusions that counsel assisting the royal commission came to about Julia Gillard were very damning indeed,” he told Network Ten.

The attorney-general suggested this substantiated the coalition’s pursuit of Ms Gillard when it was in opposition.

“I think it’s enough to say that the conclusions Mr Stoljar came to … certainly justify the concerns that people like Julie Bishop, Tony Abbott and others raised in the last parliament about Julia Gillard’s conduct at the time.”

The former Labor leader says the royal commission found she committed no crime.

Her lawyers will be making further submissions to the commission at the appropriate time.