Buildings on North Fremantle's battered Port Beach may have to be moved significantly inland in coming years to save larges stretches of the Perth coastline from the advancing ocean.

Key points: Experts say Port Beach won't exist in the future if erosion isn't addressed

Experts say Port Beach won't exist in the future if erosion isn't addressed Popular beaches including Scarborough, Trigg and Floreat are also under threat

Popular beaches including Scarborough, Trigg and Floreat are also under threat The City of Fremantle is considering a "managed retreat" of the coastline

The controversial proposal could be the only hope for retaining beaches like Port Beach, according to one of the experts behind a new report on Western Australia's coastal erosion hotspots, which is being considered by the State Government.

Recent storms left buildings at Fremantle's Port Beach teetering on the edge of collapse.

Relocating current infrastructure is one of a range of options being considered by the City of Fremantle, along with the construction of a seawall and groynes to fortify the coastline.

Infrastructure along Port Beach is under immediate threat. ( Supplied: City of Fremantle )

A 'managed retreat' from the ocean

The council has started dumping tonnes of sand in front of buildings on the beach as a temporary bulwark, but Mayor Brad Pettitt conceded it was a band-aid solution to protect the Coast restaurant, changerooms and Fremantle Surf Club annex at Port Beach.

Machinery was recently brought in to help manage erosion problems at Port Beach. ( ABC News: Nicolas Perpitch )

Mr Pettitt said he believed shifting the existing infrastructure, including Port Beach Road, was necessary to preserve the beach in the long-term.

"In a perfect world you wouldn't have infrastructure like changerooms and restaurants so close to the ocean," he said.

"What we should be doing is managed retreat, which is putting everything much further back — everything from roads, to the changerooms, the [Coast] restaurant.

"Port Beach Road in its current alignment needs to be set a long way back from where it currently is."

Mr Pettitt said relocating the road and other infrastructure significantly back from the tide line would allow for a foreshore reserve.

Fremantle Mayor Brad Pettitt believes shifting infrastructure is the best way to ensure the future of Port Beach. ( ABC News: Rhiannon Shine )

Coastal engineer Matt Eliot said Port Beach would likely cease to exist in the future unless the infrastructure was removed.

"In 20 to 30 years' time there is unlikely to be a beach at Port, unless we choose to retreat," he said.

"Otherwise we will just have a sea wall."

'A near catastrophic set of circumstances'

Coast restaurant owner Ian Hutchinson, who has 12 years left on his lease, said coastal erosion was a serious threat to his business.

"It is a near catastrophic set of circumstances — it is as serious as it gets, from my point of view," he said.

Coast restaurant owner Ian Hutchinson doesn't believe a managed retreat is the answer. ( ABC News: Rhiannon Shine )

Mr Hutchinson said managed retreat was not the answer, but he did want work to start urgently on a sea wall or another form of preventative infrastructure.

"I think we are a long way off having no beach," he said.

"It is a bit sensationalistic, [that] argument.

"You can't just keep moving back to the road, and then back again, and back again. Where does it end?

"They might as well stop it [the erosion] now and building a sea wall would do that."

More than a decade of sustained retreat

A draft report providing long-term options to manage the erosion risk at Port Beach is expected to be released for public comment later next month.

Mr Eliot's company, Seashore Engineering, has prepared a separate report for the State Government on Western Australia's coastal erosion hot spots.

The report, currently with the WA Government for consideration, found the state's beaches would likely face increasing problems with coastal erosion in the coming years.

Experts agree something needs to be done to tackle erosion problems at Port Beach. ( ABC News: Nicolas Perpitch )

Mr Eliot said Port Beach was the Perth site under the most imminent threat.

"Port has suffered 15 years of sustained retreat so putting in a bit more sand is starting to become a not very viable treatment, and they will need start to make decisions about defence or retreat very soon," he said.

"Defence involves putting some form of coastal engineering structure in [such as] groynes or sea walls, and the retreat option is where you are actually starting to remove everything from the site — so take the buildings away, remove the roads, put the roads into a new location.

"They are likely to need to relocate the road at some stage."

Similar fate awaits city's most popular beaches

Mr Eliot said other Perth beaches likely to be seriously affected by coastal erosion in the next 20 to 30 years included Leighton, Scarborough, Trigg, Mettam's Pool and Floreat.

"In 20 to 30 years' time we will move from having them as seasonally wide beaches to occasionally narrow," he said.

"We will end up having the beach move back and cut into the dune areas. So we will have dune scarps likely to occur within about 10 years [and] we will have much shorter beaches.

"At Cottesloe, for example, we will move from having one year every 10 years where rock starts to be exposed, to being exposed every two or three years.

"We don't have unchanging beaches. You can't expect for things to be exactly the same as they were for the last 20 years."

Mr Eliot said the State Government would likely need to spend between two and five times the current level of funding on coastal defence in the coming years.

Coastal engineer Matt Eliot says Port Beach is the Perth beach under greatest threat. ( ABC News: Rhiannon Shine )

According to the City of Fremantle, continued access to Port Beach Road, North Mole and the Inner Harbour would be key considerations when evaluating the retreat option.

Appeal for state support

Mr Pettitt said the city would not be able to proceed with the re-location without the support of the State Government and Fremantle Ports.

"It is beyond the capacity of local government to do it by ourselves," he said.

"We would need to work with the State Government to do that because this [land] is ultimately on state reserves."

Volunteers have been planting spinifex in dunes at Floreat Beach in an effort to hold back erosion. ( ABC News: James Carmody )

Transport Minister Rita Saffioti said she was in discussions with the City of Fremantle about possible solutions.

"We want to work with councils to get more permanent solutions," she said.

"We will engage with the City of Fremantle to see what options they are putting forward."

She did not comment on whether relocating Port Beach Road and other infrastructure was a feasible option.