Shipwrecks that for decades have lain untouched on remote beaches in Perth's north are being threatened by residential development and human interference.

There are 15 shipwrecks along the City of Wanneroo's 32-kilometre coastline that up until recently were only accessible by off-road tracks.

The region is one of the largest growing areas in the country, adding 8,000 new residents a year.

Tracey Roberts, the city's mayor, said encroaching housing development meant the hitherto remote wrecks were at a greater risk of vandalism.

The city has launched a new mobile phone app sharing information about the wrecks which Ms Roberts hopes will persuade people not to interfere with them.

"I think you become more respectful when you know the history," she said.

"They needed to be treated respectfully so they're around a long, long time for future generations."

The Alex T Brown is one of the few exposed beach wrecks in Perth. ( Supplied: Neptunes Photography )

Protecting one of WA's best wrecks

In 1917, the 800-tonne sailing ship Alex T Brown ran aground just south of Two Rocks soon after leaving Fremantle bound for Manila.

Ross Anderson, curator of maritime archaeology at the WA Museum, said it was one of the state's most spectacular beach wrecks.

"It's one of the few wrecks in the metropolitan area that the public can actually see and experience.

"At the time it ran ashore, it was a source of materials for the early settlers in the area.

"They recovered timber from the wreck to build some of the early homesteads."

Ross Anderson explores underwater shipwrecks for the WA Museum. ( Supplied: West Australian Museum )

Earlier this year the wreck was set upon by vandals who sawed off pieces of wood.

It prompted the introduction of state legislation that could see people fined up to $1 million for interfering with the wreck.

"You can actually see where people have taken parts away," Ms Roberts said.

"To actually have that at their home, some people probably feel quite proud, but it didn't do us any favours."

A haunting history

In 1963, a cargo ship called Alkimos became stuck on a reef north of Quinns Rocks after a series of mishaps on the water.

"They tried to tow it to Fremantle, it caught on fire, then it was impounded," Dr Anderson said.

"They were trying to tow it up to Hong Kong for some further repairs and then the tow line broke and went aground.

"Then they towed it off again but then the tow line broke again and it went ashore again on the reef and that's where it stayed."

The Greek freight ship Alkimos was quite a sight after coming aground near Quinns Rocks. ( Supplied: City of Wanneroo )

Dr Anderson said only a small part of the ship remains after much of it was sold for scrap in 1965.

"Gradually over the years it's just disintegrated, it's just a steel ship in a corrosive environment so there's not much left of it showing now.

"It did look quite impressive, a large cargo ship stranded there for many years."

Ms Roberts said some locals believed the ship was haunted by a ghost.

"Way back, the locals said when horses used to go up and down the beach, they would not go beyond the Alkimos wreck," she said.

"The horses would get quite skittish."

Alkimos was being towed to Hong Kong when it ran aground in 1963. ( Supplied: City of Wanneroo )

When heritage is gone, it's gone

Dr Anderson said Western Australia's coastline was a treasure trove of maritime heritage.

"A lot of beaches have these shipwrecks that have been blown ashore and all the top parts disintegrate in the surf but the lower part can be quite well preserved in the sand."

At the time, the cargo shipwrecks were huge financial disasters for their owners and the fledgling colony.

"It's like a Bunnings Warehouse washing up on the beach; there's a lot of material and goods on board," Dr Anderson said.

"These ships were carrying an incredible amount of merchandise and everything needed for the colony in the early days.

"The government, the people and the traders were waiting for their consignments, so it was a huge disaster and a pretty small community at that time too so they definitely had a massive impact."

Little remains of the Alkimos after it was auctioned off for scrap more than 50 years ago. ( Supplied: City of Wanneroo )

He said it was important for government to put measures in place to protect shipwrecks from further deterioration.

"Heritage is not like whales and rainforests which if they're protected they're a renewable resource — with heritage sites once they're gone, they're gone."