It has been referred to as an "ambitious target", but hopes remain high that Sydney's Parramatta River could be safe for swimming by 2025.

However, some believe it will not happen unless the State Government changes its emphasis on Sydney's development.

The Parramatta River Catchment group has reintroduced swimming at Parramatta Lake further upstream and their goal now is to make more of the river usable for swimmers.

Yesterday, the group held Riverfest, a free family day celebrating life on the river on the bank at Putney.

The waterway is already used for boating, including dragon boat racing, but swimming has been banned there for decades.

Crowds enjoying the Riverfest event on the banks of Parramatta River. ( ABC News: Liv Casben )

Senior Lecturer at Macquarie University Peter Davies said state and federal governments need to prioritise creating liveable cities, instead of continuing to pursue their housing and economic targets.

"Urban planning has mostly been around provision of housing and certainly the environmental concerns have been seen as subordinate," Dr Davies said.

Dr Davies said the key driver behind the initiative was to create a goal for the community.

"One of the most critical reforms that this group has managed to do is enable swimming in Lake Parramatta," he said.

"That's a clear expression of how aspiration has become reality."

He said there were spots along the Parramatta River where there was "sufficient tidal flushing where there's not that residual contaminant loading on sediments" where swimming may be possible.

"If you are going to ask me am I going to do laps from the Harbour Bridge to the Parramatta Wharf, probably not in 10 years," he said.

"Clearly, a 10-year target from today is an ambitious goal."

He said more cooperation was required between government bodies and agencies.

"When I see the current level of government coordination and the range of government agencies involved and who has a stake, there is not the coordination that there could be," Dr Davies said.

"You've got legacy contaminants, dioxins a whole bunch of really intractable pollutants in terms of their immediate and local impact on environment."

Group working on master plan for river

Ryde Mayor and Parramatta River Catchment group chair Jarome Laxale said the group was working closely with Sydney Water and the Environmental Protection Agency to come up with a master plan on how to clean up the river by 2025.

"We are on track … we've been surprised by the results … we've had better water quality … we've seen a lot of reduction in some of the chemicals that used to be found in the river," Mr Laxale said.

"Remember, Parramatta was a dumping ground for industry.

"If you think back to what governments and agencies did with beaches and the harbour, there was a real concerted effort to change the culture … we're now doing the same thing with Parramatta River.

"Each and every day we're seeing better results down the river and that's something to be proud of.

"Last year, we had the announcement that the three swimmable areas now are Dawn Fraser Pool, Cabarita Park and Chiswick … we've seen dolphins as far inland as the Silverwater Bridge, so we're really making progress."

Members of the Parramatta River Catchment group on the riverbank yesterday. ( ABC News: Liv Casben )

He said there were 22 swimming sites across the river when people could swim in the waterway 60 years ago.

"We've chosen about eight or nine to undertake some heavy testing, testing the sediment, testing the water quality and I guess making a map, or a list on what we need to do to clean it up," Mr Laxale said.

Mr Laxale said that would help the group compile a master plan and to determine how much funding and government assistance was required.

"We're at very early stages, but already our advocacy and events such as these changing the culture."

River was 'grey and it stank'

Former Meadowbank resident Steve Cozens said the river was now much cleaner than it used to be.

"The water was grey and it stank, it was really badly polluted, but it's really changed a lot now," Mr Cozens said.

"It's quite clean-looking and there's a lot of bird life … it's improving as a habitat."

He said that he might swim in the river if all steps were taken to make sure that it was clean.

"It's certainly getting cleaner and cleaner, because the amount of wildlife you see must be indicating something," he said.

"It's been a long time coming.

"They're making a good go of making the river attractive, there's walks everywhere … it's obviously becoming a better environment."