State Government documents have warned up to 2,500 buildings in New South Wales could be fitted with flammable cladding similar to that which was engulfed in the London Grenfell Tower fire this week.

In the September 2015 document obtained under Freedom of Information by the NSW Opposition — marked "in confidence" — the Department of Planning and Environment states the potential number of building affected by combustible cladding could be between 1,500 to 2,500.

Cladding materials have been in the spotlight since a 2014 Lacrosse building fire in Melbourne, and Wednesday's dramatic London blaze, in which 17 people died.

Today the NSW Minister for Emergency Services, Troy Grant, could not be exact about the number of buildings fitted with potentially dangerous panels.

Troy Grant says the London fire has sparked action from people in the NSW Government. ( AAP: Lukas Coch )

"It's an ongoing process, obviously buildings go up, buildings come down, they change, obviously it's not something that sits still in time," he said.

"And as a result of the London incident they're reaching into local government to see the status of where up to and if there is more that needs to be done in relation to any potential risk across the state."

In a statement late today Planning Minister Anthony Roberts told ABC News: "A previous estimate of 1,500-2,500 buildings does not represent the scale or number of affected buildings."

"There is no known data source on the location of buildings with aluminium composite panelling."

Thousands of buildings could be affected

But Local Government NSW president Keith Rhoades said 2,500 buildings could be an under-estimation.

"It's entirely possible this figure would be significantly higher today," he said in a statement.

"There did not appear to be a single source of truth on the number of buildings in NSW that might have used the same cladding as in the London fire, or in a 2014 fire at Melbourne's Docklands precinct — or indeed on buildings using other non-compliant products that may pose safety risks."

When the Melbourne's Lacrosse complex caught fire in November 2014, external cladding was considered a factor in the ferocity of the blaze.

The Victorian government spent $1 million on an audit of other high-rise buildings and found there were risks associated with another 80 buildings.

Opposition calls for Victoria-style review

While the NSW Government has defended its actions since, including making "councils aware of the risks of non-compliant cladding on high-rise buildings" and a National Construction Code with enforceable powers, the Opposition has labelled it "a lazy approach".

The Opposition's better regulation spokeswoman, Yasmin Catley, called for the Government to undertake a similar audit to Victoria.

"What are they doing to make people feel safe in their dwellings?" she asked.

Ms Catley told the ABC that local government may be best place to conduct an audit but she wanted it to be properly resourced.

A spokesperson for the City of Sydney said they were not aware of any buildings that had non-compliant cladding.