The City of Melville has approved the next step of the $25 million Alfred Cove wave park project, but key conditions of the lease will be debated behind closed doors.

At an animated council meeting tonight attended by about 300 people, City of Melville chief executive Shayne Silcox was authorised to draft a lease proposal with Wave Park Group.

Once that lease is drafted it will be discussed at a closed full council meeting.

Council officers had recommended giving the chief executive the power to draft and execute the lease. That would have enabled the proponents to proceed with a formal development application.

Bull Creek Leeming councillor Matthew Woodall said councillors should take ownership of the final decision, rather than the chief executive alone.

“There's the potential it might not work out and, if so, the consequences are greater for a development of this size,” Mr Woodall said.

Camera Icon The proposed wave pool at Tompkins Park in Melville, near the river in Alfred cove. Credit: Supplied

Wave Park Group founder and executive chairman Andrew Ross expressed frustration at the opposition to the project.

“We are confident of funding the development if the project goes through at this site,” Mr Ross said.

Residents for and against the park overflowed into a room outside the council gallery where they could hear the meeting, exclaiming as council members entered the meeting or made remarks on the project.

Dozens of members of Alfred Cove Action Group wore t-shirts with “no waves - protect Alfred Cove” written across them.

Attadale residents Garth and Diane Curran, members of Alfred Cove Action Group and wave park opposition group Swan River Estuary Action Group, were disappointed with the decision.

“We are upset but we prepared for it,” Mr Curran said. “We've got a big fight on our hands.”

The Currans are part of a group of residents who plan to pursue legal action against the City of Melville over the wave park.

Like many residents at the meeting, the couple did not oppose a wave park - just its proposed location.

“It's an A class reserve and it’s the last bit of wetlands on the Swan River,” Mr Curran said.

City of Melville Mayor Russell Aubrey, on the advice of the council’s lawyers, criticised the legal argument put forward by residents.

He said a letter prepared by Lavan Legal on behalf of residents against the wave park contained “errors and omissions”.

Dr Silcox could not put a date on when a decision on the lease would be made.