A 60-hectare stretch of land in Appin will be given to the public if the Liberal Party is elected to government next weekend.
State Environment and Heritage Minister Gabrielle Upton joined Wollondilly Liberal candidate Nathaniel Smith to make the announcement in Appin this morning, promising $5 million would be allocated to "improve" the space.
Mr Smith said this was a "magnificent announcement".
"This 60 hectares of land stretches from Appin Road to the Georges River and we have $5 million to deliver what the community wants, which we will find out from community consultation," he said.
"Whether that's cycleways, sporting fields, barbecue areas - the community will let us know.
"If people want to see more green space, vote one for the Liberals on March 23."
The land in question is opposite the Appin Valley housing development off Appin Road.
The Environment Minister said the parklands would "improve the quality of life in Appin".
"It's now over to the community to bring up their good ideas - they will know how best to use this land," Ms Upton said.
"It's beautiful and it's going to be theirs.
"Nathaniel Smith and I are very keen to get this moving very quickly.
"We know the community wants their open space - they can look at it at the moment, but we're going to open it up so they can enjoy it.
"It's highest priority."
The announcement also allowed for a third of the land to be set aside as protected koala habitat.
Mr Smith said he took the preservation of Macarthur's disease-free koala colony very seriously.
"Koalas are a big issue here and we want to get the science of it right," he said.
"Wherever there is koala habitat, we will do our absolute best to preserve that and we will work with the community and listen to their views on how to get the best outcome for Appin."
Ms Upton said the environmental assessment would inform exactly what the dedicated koala habitat would look like.
"We believe there are koalas here and we know the local community love their koalas - they're environmentalists.
"The assessment of 20 hectares [for koalas conservation] is not a fixed number - we really need the scientists to tell us what we have and what the proper dimensions of the koala habitat are."
Despite the politicians' enthusiasm for the announcement, local environment campaigners Sharyn Cullis (of the Georges River Environmental Alliance) and Sue Gay (of the Appin Historical Society) were less than impressed.
"Public open space should already be factored into the developments we've got here, not a separate announcement," Ms Gay said.
"There are beautiful young families here in Appin Valley, with thousands of young children, and they've only got a tiny play area that's beside a detention pond [designed to protect against flooding] which has been classed as green space - it's bloody ridiculous."
Ms Cullis was equally unenthused.
"To bring this out as an announcement is an insult to all of us as voters because it's an obvious knee-jerk reaction and last-minute political promise," she said.
"This whole space could be part of a national park - it could be an extension of the Georges River National Park. It deserves to be."