A $400 million coastal development is being reviewed by the State Government after data revealed that parts of the site could potentially be plunged under water because of rising sea levels.
Planning Minister John Day revealed the Port Kennedy development, on the coast of Warnbro Sound, had become financially unviable in light of new climate change predictions.
Recently updated Department of Planning guidelines on coastal setbacks predicted sea levels could rise 0.9m in the next 100 years, instead of 0.38m as previously forecast.
As a result, the developable land area agreed to by the Government and developers Western Australian Beach and Golf Resort Pty Ltd in 2004 has been greatly reduced.
Mr Day told Parliament the project was no longer feasible and had to be redesigned.
The project is understood to be the first development to be affected by new sea level predictions.
One of the biggest beachside developments planned in Perth, the Port Kennedy project was to be a mixed-use residential and tourism hub with 128 ecotourism units and about 650 dwellings. It also included boating facilities, a boardwalk network, public jetty and nine-hole public golf course.
Managed by Mirvac on behalf of WABGR, construction started in 2010, with public works, including a boat ramp, already completed.
Mirvac development director Kim Lawrance said the company remained committed to the project but parameters and time frames would need to be revised. Mr Lawrance said he believed more land would be released for development to compensate for the reductions.
A spokeswoman for Mr Day said community members and stakeholders would be notified of the changes in the coming days but only vacant land was affected by the increased setbacks.
But she could not say whether existing properties in the area, including those at the established Long Beach Estate, would need to be adapted because of the sea level predictions.