The proposal would see the 18-hole Eastlake golf course converted into a major new public park, as part of the City of Botany Bay's Vision 2040 Directions Paper; the penultimate step in the 25-year vision for Botany Bay.

"The last five years has seen around 3000 new dwellings added to the Botany area, with another 4000 expected in the next 10 years ... people need access to public space," City of Botany Bay Mayor Ben Keneally said.

The announcement comes after a Fairfax Media report on Monday found NSW councils have sold, developed or reclassified more than 20 per cent of public urban open space in the past decade.

The situation has been described as "incredibly alarming," by Nature Conservation Council chief executive Kate Smolski, meaning Tuesday's proposal to increase open space in Sydney's east should be welcome news.

"With urban consolidation and the desire of more and more people to live closer to the CBD, there is an increasing population that wants places to enjoy Sydney's great beauty," Mr Keneally said.

"The Botany wetlands are beautiful, but they are a hidden gem. They've been locked up inside these golf courses and inside industrial estates."

Mr Keneally said, while private sites were once a great way to protect the wetlands, "we now know communities value these great ponds and lakes and the social and environmental heritage they contain, and they would love better access to them."

The park would connect from Gardeners Rd, Daceyville, all the way to Sir Joseph Banks Park on the shore of Botany Bay, following the course of the Botany Wetlands.

Neighbouring the public Eastlake Golf Club is the exclusive Bonnie Doon Golf Club, The Lakes Golf Club (both owned by Sydney Water) and the country's most eminent, The Australian Golf Club.

The land on which the club is situated is owned by Sydney Water and leased to the club, which is currently operating on a 25-year lease.

While there is a 25-year option to renew, the current lease will expire at the end of December 2025, falling well within the time frame proposed for the parkland project.

"We're not proposing to destabilise their existing tenure. It's in line with security of tenure they currently have.

"The club's response has been that it will be a matter for the landlord to determine, being Sydney Water."

Calls by Fairfax Media to Eastlake Golf Club general manager George Kozis were not returned.

A Sydney Water spokesperson said it would work closely with the relevant parties on any future plans for the Botany Wetlands.

"Ultimately, Sydney Water will work to ensure that any future use of the wetlands provides benefits to the community and environment."

But not everyone would be pleased with the idea. Paul Saltoon has been playing golf for more than 20 years, and often has a hit at the Eastlake course.

The Bondi local said he "would be pretty upset if the course was taken away for that use".

"Even if you only play three times a year, when you're on that golf course you feel like you're away from all that Sydney hustle and bustle."

The Botany Bay 2040 Directions Paper also proposes a plan for the council-owned Botany Golf Course to be converted to provide more sporting fields to a wide variety of organised sport such as football, league, netball and rugby.

Mr Keneally said council would be working closely with stakeholders over the next 20 years on the site's transition.

"The proposed parkland should become a significant addition to the Centennial Parklands as it follows the same hydrological flow path as the Centennial Ponds and boasts historical plantings from the era of when the Royal Botanical Gardens were established."