02/11/2016 7:40 PM AEDT | Updated 03/11/2016 7:33 AM AEDT

Attorney-General George Brandis Says He Wasn't Aware Of Questions Over Bob Day Two Years Ago

'I'm not familiar with that.'

Attorney-General George Brandis said he 'had no knowledge' of the federal government enquiring about Day two years ago.

The elections of two crossbench senators have been brought into question this week, as it emerged that Family First Senator Bob Day and One Nation Senator Rod Culleton may have breached the Constitution.

Attorney-General George Brandis and Special Minister of State Scott Ryan are seeking the Senate's approval for the High Court to investigate the possible invalid elections.

The possible breach of constitution by Bob Day

There are claims that Day has a financial interest in the building where his Adelaide parliamentary office is located, meaning the government has been renting office space for Day from a company that he himself is involved with. This would come up against part (v), which says someone is disqualified from parliament if they have "any direct or indirect pecuniary interest in any agreement with the Public Service of the Commonwealth".

On Wednesday night, Brandis said on the ABC's 730 program that he only became aware Day possibly breached the Constitution last Thursday.

When Leigh Sales said the then Abbott government first sought advice from the finance department about the location of Day's office in February 2014, Brandis said he had no personal knowledge of that.

"I'm not familiar with that. I wasn't minister at the time. I have no knowledge," Brandis said.

Sales went on to query whether the Attorney-General had familiarised himself with this, since the matter may be referred to the High Court. Brandis responded simply, "No, I have not".

"What I'm saying to you is that whatever happened in 2014 involving the Special Minister of State is not something about which I can speak," Brandis said.

The Attorney-General also said he'd been notified by Rod Culleton that he would not be voting on any contentious bills in the Senate while questions over his election remained.

The possible breach of constitution by Rod Culleton

This year, Culleton pleaded guilty to a larceny charge, which involved him stealing a key from a tow truck driver in Guyra, in northern NSW in 2014.

Brandis said "Senator Culleton had been convicted of an offence punishable by a sentence of imprisonment for one year or longer, and was therefore "incapable of being chosen" as a Senator under section 44(ii) of the Constitution.

Brandis said he had not yet seen Culleton's "colourful" press conference addressing the controversy, but said the One Nation Senator is a "decent" person.

"I spoke to him on Saturday. What he said to me was that he assured me that, as an honorable person, he just wanted to do the right thing and I'm sure that is where his mind is at," Brandis said.

UPDATE: This story has been updated to reflect that Attorney-General George Brandis was unaware of questions the Government had raised about Senator Bob Day's pecuniary interests two years ago.