The Adelaide Park Lands Association says the government's consultation process, which opened on Tuesday, envisages no sites other than on existing parklands.
The group's president Shane Sody has written to Premier Peter Malinauskas detailing multiple other brownfield sites around Adelaide that could be used.
It has also established a community survey offering up a range of alternative locations.
"We will be providing real feedback, from an open-ended survey, showing that the government does not need to attack Adelaide's open green public parklands to deliver a first-class new aquatic centre," he said.
Infrastructure Minister Tom Koustantonis said the government's consultation process would focus on three proposed locations on existing parklands.
He said any of the three sites would allow the existing facility to remain open during construction of the new centre.Â
Once the new centre is opened, the existing Adelaide Aquatic Centre will be demolished and returned to parklands.
"We are committed to building a new facility that meets the needs and expectations of the community and is able to be utilised for the long-term," the minister said.
"This will be a centre that is used by residents across many different communities in and around Adelaide's CBD, and it is important that those communities have their say in its future."
The government plans to own and operate the new centre after making it a key election promise.
The existing facility, operated by the Adelaide City Council, has long been considered no longer fit for purpose.