The government's public backing of the council comes after Liberal Member for Yerrabi James Milligan wrote to Heritage Minister Mick Gentleman and City Services Minister Chris Steel about the proposal on Wednesday.

Mr Milligan raised questions about the council's decision being made out-of-session and against the advice of representative Aboriginal organisations.

He said the Hall community had campaigned for the bike track for years and that the issue had dragged on too long.

"It is vital that a decision is made urgently with transparency and integrity," Mr Milligan wrote in the letters.

The ACT Heritage Council decided in October not to approve construction of the proposed track at Halls Creek, citing its effect on Aboriginal heritage and recommending that it be built elsewhere.

A statement of heritage effect prepared by Navin Officer Heritage Consultants shows the firm consulted representative Aboriginal organisations on the proposed track, receiving support from King Brown Tribal Group and using Buru Ngunawal Aboriginal Corporation's feedback to develop protocols for relocating any Aboriginal artefacts found.

Despite this and Navin Officer's report assessing the project's impact as minimal, the council decided to reject the proposal through out-of-session assessments, with no meeting minutes available.

The Sunday Canberra Times has previously revealed that while Heritage Council deputy chairman Dr Ken Heffernan did not take part in the council's consideration of the project, his public commentary on the track being built in the proposed location at Halls Creek prompted a resident to raise conflict of interest concerns with the government.

It was also Dr Heffernan's partner, Dr Jan Klaver, found Aboriginal artefacts in the area surveyed for the bike track in December 2017.

A spokesman for Mr Gentleman said the council's Aboriginal taskforce had considered the bike track proposal and found it would lead to the destruction of stone artefacts.

"We are confident in the ACT Heritage Council and trust its decisions and integrity," the spokesman said.

"The [ACT Heritage] Council is the ACT government’s key advisory body on heritage and members are appointed based on expertise.

"In accordance with the Heritage Regulation 2006, the ACT Heritage Council can conduct its business via meetings, as well as out-of-session emails and phone calls and through the establishment of taskforces and delegations.

"Council members do not consider applications relating to the suburb where they live. Upon appointment to the Heritage Council, Dr Ken Heffernan declared a conflict of interest in all matters pertaining to the suburb of Hall and does not participate in Heritage Council business related to Hall."

In his letter to Mr Gentleman, Mr Milligan, the Canberra Liberals' indigenous affairs spokesman, asked the heritage minister questions including whether he trusted the integrity of the Heritage Council's decision and whether he had the power to overrule decisions the council made.

Mr Gentleman's spokesman told the Sunday Canberra Times while ministerial call-in powers could be used to overrule a decision on a development application, such powers did not exist under the Heritage Act and no development application had been lodged for the proposed bike track.

A spokeswoman for Mr Steel said Transport Canberra and City Services was working to identify a new alternative site for the proposed bike track.

"Once an alternative site is identified, the directorate will further brief the Minister for City Services on progress," she said.

"The Hall recreational trail will provide additional recreational opportunities for families in the Hall community and Transport Canberra and City Services will work with all parties involved to assist in facilitating the community’s proposal."