Attorney-General George Brandis has said he was not aware of a political donation made by a Brisbane solicitor who he promoted to the Administrative Appeals Tribunal (AAT).

He has defended his professional relationship with Theo Tavoularis, who provided a $1,200 donation to the Liberal National Party of Queensland in 2013.

Mr Tavoularis was promoted to the AAT in the days before the start of this year's federal election campaign.

In a statement, a spokeswoman for Senator Brandis said the appointment was entirely within the agreed protocol for appointments.

His colleague Alan Tudge told the ABC that Mr Tavoularis should be "assessed on merit" and not ruled out from positions due to past donations.

"Just because he happened to have provided a donation to the Liberal Party in the past should not exclude him from being appointed to such a position in the future," he said.

The spokeswoman declined to comment on reports by Buzzfeed News that Mr Tavoularis acted on behalf of Senator Brandis' son Simon in a 2014 court case.

The Shadow Attorney-General Mark Dreyfus said there was a "clear conflict of interest issue" in the appointment.

"Either Senator Brandis was not aware of Mr Theo Tavoularis's history when he appointed him to this prestigious role, or the decision was made in the knowledge of the personal connection with his son," Mr Dreyfus said in a statement.

"As the first law officer of this country, Senator Brandis must not only act in accordance with the highest standards of accountability and probity; he must also be seen to act in accordance with those standards."