Melbourne Water is attempting to rezone four Melbourne sites for sale, despite three of them – in Reservoir, Rosebud and Brunswick West – being used as parkland by residents.

The fourth, in South Morang, is a 2.8-hectare site just metres from a new railway station on the soon-to-be-built Mernda line.

Around 70 residents have made submissions asking the government to abandon the sales, ahead of public hearings next month.

"This park is a jewel in our little area of Reservoir," said Alan Turner, who for 16 years has lived opposite the land Melbourne Water now wants to sell.

Mr Turner said his family, like others in the area, had paid a premium for their home because it was opposite a park.

Mr Turner's children grew up playing cricket and football on the reserve. "When they have children, they will bring them back around to my home for a visit and then go out into the park to play," he wrote in his submission to the government opposing the sale.

The four sites Melbourne Water wants to sell are all zoned for public use.

However, they have already been declared surplus by the water authority – meaning they will be prepared for sale unless a government minister steps in or a local council offers to buy the land.

The land is being rezoned for sale as part of the government's Fast Track Government Land Service.

Under that process, agencies that want to sell public land must first offer it to other government authorities before being sold on the open market. Councils are the most likely buyers.

But the Andrews government's policy of capping rates means councils have little spare cash.

Councils do collect open space contributions and one government figure on Tuesday said that parcels of land like this were precisely what those funds were meant to be spent on.

The Reservoir land that Melbourne Water says it no longer needs is a popular dog-walking and recreation reserve. While it is only a 934-square-metre parcel of land, it is part of a linear pipeline reserve running through the suburb.

In Rosebud, Melbourne Water wants to offload a massive, 5.6-hectare site used by locals for dog walking and exercise. If rezoned, the land would be worth around $400 per square metre – or about $22 million.

Craig Thomson lives near the Rosebud land, and says it is well used. "And in terms of green space, we don't have a lot on this side of the freeway," he said. "In summer, so much of the open space here is taken up by campers."

There was only one consultation meeting before the land was proposed for sale – and Melbourne Water held it in Dromana.

Mr Thomson said bureaucrats from Melbourne Water had "talked down the piece of land like it was a huge burden … they pushed that this was an opportunity to sell off the land to put investment back [elsewhere in their business]."

In Brunswick West, an active community group has formed to fight the proposed rezoning and sale of a small parcel of land attached to a larger park along Moonee Ponds Creek.

Simon O'Brien, a director of architects Six Degrees, lives near the land and argued that the state government was trying to push the costs of providing parkland on to local government despite the sites already being public. "Councils shouldn't have to go and purchase land for public parks," he said.

Melbourne Water's manager of property, Peter Morison, said the agency had a duty to regularly review land holdings not crucial to its operation.

"Should land be determined surplus to requirements, it is mandatory that all government bodies consider it for sale," he said.

He said the water authority had "a comprehensive method" of reviewing land that was no longer required to do its job.

And he said the authority acknowledged it was a serious step to ask the planning minister to rezone land that it owned for sale on the open market.

"Any decision to declare land surplus is not taken lightly," Mr Morison said.

Kaye Oddie, from the Brunswick West group, said the water authority and the state government needed to urgently rethink the land sales, given Melbourne's booming population.

"It's not as if Melbourne Water is taking away a car park – it's existing public parkland," she said.

The Andrews government's budget update last month showed the government reaped $150 million in 2016 from the sale of public land.