WA beaches, assets at risk of washing away

Coastal erosion is threatening homes, roads and public assets at 55 locations across WA

Port Beach in Fremantle and South Thomson Bay at Rottnest Island have been identified as the top two West Australian locations at risk of crumbling into the sea.

In a report released on Monday, the state government listed 55 places where coastal erosion is expected to threaten homes, roads and other public assets over the next 25 years.

At Port Beach, which is among 15 hotspots in the Perth metropolitan area, this winter's storms caused a car park to collapse and left buildings teetering on the edge.

The council used earthmovers to pile up sand as a temporary protective measure but Mayor Brad Pettitt said substantially pushing back existing infrastructure, including Port Beach Road, was needed in the long term.

The WA government estimates the cost for managing the 55 locations could be up to $110 million over the next five years and is seeking federal funding contributions.

It is focused on seawalls and groynes, and Premier Mark McGowan says retreat is a last resort.

Mr McGowan said he wrote to Prime Minister Scott Morrison about the federal government working with the states to tackle the climate change-related issue, which needs more than piecemeal solutions.

He promised to raise the matter again at COAG on Friday.

"I think it deserves a national co-ordinated response ... (it's) going to dramatically impact communities and infrastructure for decades if not centuries to come," Mr McGowan told reporters on Monday.

Where industry is present, like Kwinana Beach, it will be asked to contribute, Mr McGowan said.

The tiny hamlet of Seabird north of Perth, where a seawall was built several years ago to stop homes being swallowed by the ocean, remains on the hotspot list.

One of Perth's most popular beaches, North Cottesloe, is among 31 locations that have been placed on a watch-list for future monitoring.

At nearby Cottesloe Beach, billionaire Andrew "Twiggy" Forrest plans to replace the well-known landmark Indiana Tea House with a large new development, although keeping the existing building remains an option.

Four ambitious designs, all including a beachside pool, have been narrowed down to two.

Critics say the designs are too big and too close to the shore.

A spokeswoman for Mr Forrest's Minderoo Group said managing environmental factors including coastal erosion was being considered as part of the design process.

"Once a preferred option is chosen, it will be refined by architects and other consultants to mitigate any risks in this regard," she told AAP.

Most of the hotspots are in the regions, including the historic China Town in Broome and Monkey Mia in the Shire of Shark Bay, which is famous for its dolphins.