Mick Tsikas / AAPIMAGE

BuzzFeed News revealed last week that Brandis had appointed Theo Tavoularis, who had previously represented the attorney general's son in court, to the job in the final days before the election was called earlier this year.

Brandis has since denied he knew Tavoularis's Brisbane law firm had also donated $1,200 to the Liberal National party in 2013, one month before Brandis was made attorney general.

Under questioning about the appointment on Monday, Brandis told the Senate he personally offered the job to his son's legal representative and party donor.

"I approached him as I approach any appointee," Brandis said.