It is understood Mr House was given a deadline to step aside or face an investigation following a Fairfax Media report that that his partner, Brendan Farnhill, had been appointed to a short-term role as communications adviser to Commissioner for International Engagement Brendan Smyth. Mr Farnhill has also now resigned.

But high-ranking officials struggled to explain Mr House and Mr Farnhill's resignations in a committee hearing at the ACT Assembly on Monday, beyond saying the pair had gone for personal reasons not related to Mr Farnhill's appointment.

Liberal Jeremy Hanson asked public service chief Kathy Leigh whether either Mr House or Mr Farnhill had cited the fracas over Mr Farnhill's appointment as a reason for their resignations, and whether there had been "conversations where it was suggested that either should resign".

She answered, "Not to my knowledge in relation to that specific question, and there was nothing that was specific to my knowledge in relation to this being the cause."

Mr Hanson pushed: "I just want to confirm that nobody ... suggested or intimated in any way to either of these individuals it would be appropriate that they resign following the media reports, so these individuals acted entirely on their own initiative, and there was no suggestion to either person that it be appropriate that they resign?" The officials shook their heads in response.

Head of corporate Sue Hall said the pair resigned for "personal reasons".

"Certainly the matters came to light. Certainly within a short time the people resigned and gave their particular reasons for that," Ms Hall said.

Chief Minister Andrew Barr said he was "not privy to their overall employment status" or what motivated them to quit but he did not believe it was related to their relationship.

Mr Hanson said if their resignations weren't related to the fallout it would be "a remarkable coincidence".

It has been alleged to Fairfax Media that Mr House was told earlier this month that he would be investigated over the appointment. But he was advised there would be no investigation if he resigned within a fortnight - which he did.

Fairfax Media does not suggest the officials who gave evidence to the committee hearing were aware of this alleged conversation.

Asked about the possibility of an investigation at the hearings, officials did not confirm that Mr House was to be investigated, simply saying that investigations were not held in cases where people had resigned.

Ms Hall said, "In terms of conducting any investigation, or decision to, a misconduct investigation, that wouldn't have proceeded if that had been the case, because as we've outlined previously, if people have left we wouldn't do that."

Mr House's appointment in 2015 to the very senior role in charge of business, arts, sport and tourism has never sat comfortably with some in the public service.

At the time he was head of Clubs ACT, and he worked for many years as a senior staffer in the officer of former Labor treasurer Ted Quinlan.

Mr House was the public servant charged with appointing Liberal politician Brendan Smyth as International Engagement Commissioner in July last year, a political appointment by Mr Barr that attracted much criticism. Mr Smyth reported to Mr House.

In January, Fairfax Media reported that Mr Smyth had appointed Mr House's partner to a three-month, junior communications role in his office. The appointment was made by a panel, which included Mr Smyth.

News of the appointment caused such a fracas that it precipitated Mr House's resignation, which had been anticipated within months, but was suddenly made immediate.

Nevertheless, the officials at Monday's hearing defended the appointment of Mr Farnhill as above board.

Ms Leigh told Mr Hanson: "What you've asked is about any pressure on that [selection] panel and our understanding is they felt none. So there does not seem to be an issue in relation to that."

Ms Hall said Mr Smyth had not even been aware that Mr Farnhill was Mr House's partner when he had appointed him.

"My understanding was, no, they [Mr Smyth] were not aware of the actual nature of the relationship," she said.

Ms Leigh said at time of the pair's resignations, the directorate had been putting in place measures to manage the "perceived conflict of interest" around the relationship.

Asked after the hearing whether he had been aware of the relationship, Mr Smyth said: "I was aware that the two individuals were acquainted, however I became aware of the extent of the relationship after the recruitment process."