Lord mayor Clover Moore – along with the state member for Sydney, Alex Greenwich – has also condemned the proposal to build a 65,000-seat stadium on public open space as "another greedy land grab" by the Sydney Cricket Ground Trust.

Former Liberal leader John Brogden is preparing a report into Sydney's stadiums for the state government, which has earmarked $600 million from the sale of the state's electricity assets for sporting venues.

It is understood Sports Minister Stuart Ayres is enthusiastic about a new rectangular stadium at Moore Park, however a spokeswoman declined to comment.

As reported by Fairfax Media last week, this proposed facility would replace public open space next to Kippax Lake, an area bounded by Moore Park Road, Anzac Parade and Driver Avenue that is owned by the Centennial Park and Moore Park Trust.

The trust's chairman, Tony Ryan, said the proposal was "fundamentally inappropriate for Moore Park" because it would lead to the loss of green space, impact on heritage and due to the area's existing traffic gridlock.

"It is ironic to note that in the lead-up to the 150-year anniversary celebrations of Moore Park as a place for the public, we are instead talking about building over it for permanent private and commercial use," Mr Ryan said

"Moore Park, which is part of Centennial Parklands, is set amongst the highest density population zones in Sydney, with large-scale population growth projected in surrounding suburbs over the next 20 years.

"This is not the time to be reducing public open space, but enhancing it."

A recent City of Sydney report highlighted the acute need for active green space in the inner city, which is facing increased strain because of the area's growing population.

The council report said there could be a shortfall of 28 sporting fields by 2031, when 54,000 people would be living in apartments in nearby Green Square.

Sydney's lord mayor urged the government to put the needs of the public ahead of "the private and corporate interests who want to take over Moore Park".

"This seems to be nothing more than another greedy land grab by the men who run the SCG Trust," Ms Moore said.

"Along with the $38 million bridge across Anzac Parade, it reeks of 'empire building'."

The proposed venue's expected $800 million price tag would require the state government to significantly increase its $600 million funding commitment.

It is also risks putting the government at odds with the direction set out in its own metropolitan strategy, which has prioritised the need for a "new landmark venue for sporting and cultural events" in western Sydney.

Independent Sydney MP Alex Greenwich said the community would rally to oppose any loss of parkland, as it had done in 2010 when the SCG Trust sought to take control of the area to use as permanent car parking.

"The SCG has a long history of blatant attempts to grab public land and proven its aims are to build and park cars on, commercialise and privatise our parklands," Mr Greenwich said.

"This latest proposal is its most destructive yet and the community is ready to battle again."

Former environment minister Rob Stokes told Fairfax Media in March he was "not aware of any proposal" for the SCG Trust to take over parts of Moore Park.

A spokesman for Premier Mike Baird said: "The government will consider plans to upgrade sports stadiums in Sydney once it has received Mr Brogden's report."

A SCG Trust spokesman declined to comment.