Pierre Huetter has been a right faction leader in the Labor Party, a former staffer of Chief Minister Andrew Barr and husband of Transport and Education Minister Ms Fitzharris. Before entering the ACT Parliament a year ago, Ms Fitzharris was Mr Barr's chief of staff.

Mr Huetter works for Dowse Projects which is employed by GWS to work on its bid with Grocon to redevelop the Manuka Oval and be given rights in return to build up to 1000 apartments, shops and other developments on the site.

It emerged on Thursday that David Lamont, Labor's deputy chief minister in the early 1990s, is also working on the Manuka bid.

Mr Lamont, like Mr Huetter, works for Dowse. A government spokesperson confirmed that both men had been involved in a meeting with Mr Barr on the bid on November 30 last year, and with two briefings with bureaucrats.

Dowse's shares are 50 per cent held by Carolyn Lamont, of the same address as Mr Lamont. The other shareholder is John Dowse.

Mr Lamont did not return calls on his involvement on Thursday. Mr Huetter did not answer questions, referring queries John Dowse.

"I'm sort of not able to speak about my work," he said. "It's not my role in the organisation."

Dowse keeps a low profile with no discernable online presence.

Mr Dowse sent an email in response to calls, saying Dowse, which had 10 staff, had been engaged by the Giants as project managers, construction management advisers, to deliver "commercial partnering arrangements", to engage and manage sub-consultants, and for consortium governance.

A spokesperson for Mr Barr said he had "seen nothing to suggest there is any conflict in this situation".

"Minister Fitzharris has done the appropriate thing at every stage to make sure of that," he said, suggesting the scrutiny was connected to Ms Fitzharris's sex.

"In 2016 any suggestion that a woman might be conflicted, [or] cannot appropriately manage a perceived conflict, because of where her husband works is concerning," he said.

"Minister Fitzharris has been very open about her relationship with Mr Huetter. She has sought advice from the Assembly's ethics and integrity adviser and ensured there is no real or perceived conflict of interest. This is exactly the exemplary standard of integrity the Chief Minister demands from his ministers."

A spokesperson for Ms Fitzharris said she had sought advice from Assembly Clerk Tom Duncan and ethics and integrity adviser Stephen Skehill when she entered Parliament.

Mr Skehill had advised that she should always act with integrity, honesty and transparency and disclose any perceived or real conflict of interest at the earliest opportunity, which she had done.

She had written to Mr Barr about her husband's employment with Dowse Projects and told him that if a project involving Dowse came before her as a minister or in cabinet, she would "take any necessary action to avoid a real or perceived conflict of interest", including removing herself from discussions or deliberations.

"At this point in time this has not been required," she said.

Neither Mr Lamont nor Mr Huetter have signed up to the ACT Lobbyist Register.

Another consultant closely connected to the government, Dan Stewart, is also working on the Manuka bid. He is also not registered as a lobbyist, prompting the Greens' Shane Rattenbury to refuse a meeting with him to discuss the casino, another project with which Mr Stewart is involved.

Mr Stewart left his job as deputy chief executive in the government's Land Development Agency in August last year when he went to work for Elton Consulting. Elton's job on the Manuka Oval bid is in community consultation rather than government liaison.

Lobbyist rules require anyone who communicates with a politician, a staffer or a public servant on behalf of a third party to be registered. Lobbying is defined as any communication with a public official to influence policies, decisions or legislation.

Mr Stewart has met with Mr Barr and others about the casino redevelopment bid but not about the Manuka bid. He told Fairfax Media in March that he would not register because his work did not amount to lobbying.

A Giants spokesman said Dowse had been working with the Giants from the start, including working with Ernst and Young to find "the right development partner". That work had led to the appointment of Grocon.

Dowse was now working to ensure local sub-contractors could be involved as much as possible.

If the project got the green light, Dowse would remain involved "throughout the duration of the project", he said.

"To the extent that any Manuka Green team members have potential conflicts of interest then the project has appropriate project governance arrangements in place."

Mr Barr's spokesman said the government would consider the Manuka bid on merit.

"The process is overseen by some of the most senior officials in the ACT government. All bids are given the closest scrutiny by the unsolicited bid panel before advice is provided to the government," he said.

The publicity received to date on the bid was further evidence that the government and the proponents wanted feedback, he said.

"The opportunity for public debate at this very early stage in a potential project's life illustrates just how transparent the process is."

Mr Lamont is caught up in the Brumbies stoush, named as a respondent, among others, in a court action being taken by Brumbies chief executive Michael Jones.