The government launched an audit of territory-owned buildings in July 2017, weeks after the deadly Grenfell Tower fire in London put the global spotlight on the use of aluminum and polyethylene cladding.

But the ACT government isn't inspecting privately-owned buildings, relying instead on insurance companies to pass on information about the presence of non-compliant cladding material.

The Owners Corporation Network have been urging the government to extend its audit beyond government buildings, arguing high-rise apartment blocks posed the greatest safety risk.

UnionsACT demanded similar action in September 2017.

Greens planning spokeswoman Caroline Le Couteur made a fresh call for an audit of privately-owned buildings during a speech this week in the ACT Legislative Assembly.

"I think it would be desirable for the minister to look at this," Ms Le Couteur said.

"I have been told by some people in the industry that there are in fact a lot of buildings which have flammable cladding in the ACT.

"I don't know if that is true or not, but that is potentially a considerable worry to anyone who is in a building that may be in that circumstance."

CFMEU ACT branch secretary Jason O'Mara said the construction union "fully supported" widening the scope of the government's cladding audit to include private buildings.

"People should not have to live in potential death traps and not be told about it," Mr O'Mara said.

Mr O'Mara could not put a figure on how many Canberra buildings might contain the material, but said it "would exist [in the city] like it does in the rest of the country".

A CFMEU-commissioned report, released last month, estimated that 157 buildings in the ACT contained combustible cladding.

That report used the results of an audit of Victorian apartments, which found 1069 contained the material, to estimate the incidence of cladding in other cities, including Canberra.

The Victorian government has announced a $600 million package to rectify 500 of the most at-risk buildings.

Mr O'Mara said developers, builders and certifiers should be held financially liable if non-compliant cladding was found in projects they were responsible for.

The Canberra Times contacted ACT building minister Gordon Ramsay's office for comment on Friday, and was told the government's position in regards to an audit of private buildings had not changed.

Mr Ramsay has previously said the government would need to consider other options if insurance companies refused to volunteer information about buildings with potentially flammable cladding.