Coalition frontbencher Senator George Brandis has bowed to Greens' demands (since December) and has stood down from a signal case before the Senate's powerful Privileges Committee.

Australian Greens Leader Bob Brown spoke to press gallery journalists this evening about Senator Brandis' secret "recusal" from the Senate's powerful privileges committee, only recently revealed in a letter to Senator Brown's and Deputy Leader Christine Milne's legal counsel.

Australian Greens Leader Bob Brown has called on Liberal powerbroker George Brandis to remove himself, or be removed, from the Senate Privileges Committee because he has pre-judged the question of the integrity of Greens Senators Brown and Milne.

"I have reminded the Senate that the Committee of Privileges has the power to recommend jail sentences of six months for Senators. It is parallel to our courts, must apply standards of justice like those of the courts and its decisions are appellable to the courts. Senator Brandis must go," Senator Brown said in Canberra today.

A week after being ruled out of order for insulting the (Greens) Speaker of the ACT Legislative Assembly, Shane Rattenbury, Liberal Senator George Brandis has withdrawn the remark and apologised in the Senate this morning.

"It was bad behaviour, in particular because it denigrated the presiding officer of another parliament, not a fellow Senator who has the ability to seek a remedy in the chamber," Greens Leader Bob Brown said today.

"Out of bad behaviour has come a good precedent in terms of Senate procedure," Senator Brown said.