Speaking during a budget estimates hearing on Tuesday, Mr Gentleman said an administrative error in the public notification of heritage consideration for the dilapidated 1960s buildings was regrettable but had not aided the government's plans to demolish and build more than 400 new privately owned units.

The comments before the ACT Civil and Administrative Tribunal considers a separate challenge to a development application for demolition of two of the three Dickson Towers on Wednesday.

"I'm not sure there was a benefit for anyone," Mr Gentleman said of the mistake.

"I don't see that there's a benefit for government in this. The [Land Development Agency] has a particular view on how it wants to proceed down Northbourne Avenue ... but at this stage there is still a lot of work to be done."

The dispute related to the government-appointed Heritage Council's decision to list about 40 per cent of the precinct for heritage protection, while the ACT National Trust branch argued all of the buildings designed by Sydney Ancher should be retained.

Last month the ACT Civil and Administrative Tribunal ruled the trust could not appeal the more limited protection listing because it had not made a submission within the required 28 days.

The public notification called for submissions to be made by October 22 last year, but rules set out in the territory's Heritage Act required submissions be received by October 20.

The National Trust did not act on threats to launch a new Supreme Court appeal.

In May, the tribunal heard the incorrect date had been an "innocent mistake" which the Heritage Council accepted was made because of official processes related to notification of the consultation. Council chairman David Flannery said the dispute was unfortunate but that the National Trust's views had been considered.

Officials took on notice questions about the legal costs of the challenge, but Mr Gentleman told the hearing only internal government lawyers had worked on the case.

Opposition planning spokesman Alistair Coe asked if the government had considered a new notification period or other options to rectify the error.

Environment and Planning Directorate executive director of strategic planning Tony Carmichael said the appeal period for the tribunal's decision had expired meaning the Heritage Council's process would stand.

Of the three Dickson Towers on Northbourne Avenue, demolition has been approved for two on the eastern side. The northern most tower will be retained.

Demolition of the Owen Flats, pair houses, three-storey flats and maisonettes built by the National Capital Development Commission will help earn the Barr government $60 million in asset recycling bonuses from the Abbott government.

The broad redevelopment plans are formed around construction of the light rail line to Gungahlin, and also include sale of surplus government office buildings and other territory assets. A series of heritage experts have argued for protection of the run-down housing, considered a unique example of post-war international modernist-style architecture.

The government plans to partner with the Gallery Of Australian Design to record the housing precinct's heritage after the buildings are torn down.

The ground floor of the Lyneham Tower is expected to house a new heritage museum as part of the development