Mr Lawler, partner of embattled former Health Services Union leader Kathy Jackson, has been on about nine months' leave for the past year. The union is now suing Ms Jackson to try to claim about $1.4 million. It has argued in the Federal Court that Ms Jackson used fraudulent bookkeeping practices to hide her withdrawal of huge sums of cash for herself between 2007 and 2010.

Fair Work Commission insiders are privately appalled at what they consider to be the erratic behaviour of Mr Lawler, who has publicly supported and even legally represented Ms Jackson at different points during her court proceedings.

Australian Bar Association president Fiona McLeod, SC, on Thursday defended the commission's president, Justice Iain Ross, against media reports suggesting he was responsible for handling the situation. While Ms McLeod would not comment on the "ongoing controversy", she said in a statement that calls for Justice Ross to deal with it were "misconceived" and commentary around this "unfair and misguided".

Justice Ross had limited powers to discipline or remove  Mr Lawler because he was appointed before the commission was established under the previous government's industrial relations regime, she said.

The Howard government appointed Mr Lawler under old legislation, which was silent on sick leave. The current law retains such entitlements for members appointed before it came into effect.  He is understood to have excused himself from all Health Services Union matters before the commission since he began his relationship with Ms Jackson. ​

"The President of the Fair Work Commission does not have the power to remove a member of the commission - that is properly only a power of the Parliament, " Ms McLeod said in the statement.

"It is a matter for the Parliament as to whether it wishes to consider legislative amendments to the Fair Work Act to deal with the current vacuum in the legislation."

Any such changes needed to be "proportionate" and not impact on commission members' independence, she said.

A spokesman for Employment Minister Eric Abetz declined to comment on whether such reforms would be considered: "The Fair Work Commission is independent of government and its members are independent quasi-judicial  officers.

"The long-standing position has been that it is not the relevant minister that determines whether members remain in office, but rather, this power rests with the Governor-General and the Parliament."

A spokesman for Senator Abetz has reportedly said he had not received complaints from Fair Work or any other party about Mr Lawler.

Any questions regarding the conduct of any Fair Work Commission member, he said, were  Justice Ross' responsibility, News Limited reported.

A spokeswoman for the Fair Work Commission declined to comment. Justice Ross has never publicly commented on the issue.