There are fears of an oversupply of apartments in Perth that could collapse prices and leave investors out of pocket, as the housing market slows and population growth tapers off.

Key points: Spike in apartments due to be completed in Perth in next two years

Spike in apartments due to be completed in Perth in next two years Population growth has slowed to sluggish 1.3 per cent

Population growth has slowed to sluggish 1.3 per cent Perth apartment prices lower than Sydney or Melbourne

Perth apartment prices lower than Sydney or Melbourne Planned developments may be shelved

There are 3,085 apartments forecast to be constructed in Perth next year, with almost double that number - 5,668 apartments - due to be finished in 2018, figures from Y Research show.

Some of that stock will be put on the market at a time when listings have spiked.

This week, there were about 3,332 units for sale across the city, which includes all attached dwellings.

Two years ago, there were 2,104 units for sale in the same week, according to the Real Estate Institute of WA (REIWA).

Meanwhile, Western Australia's population growth has slowed, reducing the demand for housing in Perth.

At its peak, the state's population growth was 3.7 per cent in the year to September 2012.

Three years later, the rate was 1.3 percent, with net overseas migration to WA falling from 57,000 people per year, to 14,000.

Property analysts divided on oversupply

The rapid fall in WA's population growth rate means Perth may face an oversupply of apartments, according to CoreLogic RP Data head of national research Cameron Kusher.

"On a historic basis, the level of unit approvals is currently extremely high," he said.

"It will all really depend on how many of these actually get the level of pre-sales to go-ahead.

"If they are all to go ahead, you would say that it does look like the Perth market will have a bit of an oversupply of units."

But some analysts argued there was no risk of a glut of unsold stock, because banks would not lend money to developers unless enough apartments were sold to cover their debt prior to the start of construction.

Others said the growing proportion of foreign buyers in the Perth market would provide a floor for demand.

Nedlands-based Indo-Pacific Group started marketing Perth apartments to buyers in Asia about a year ago.

Managing director Daniel-Paul Filippi said demand was strong from countries that had traditionally invested in Perth, such as Singapore and Malaysia, but interest from China was also growing.

"Chinese buyers are now actually asking for Perth specifically," Mr Filippi said.

"Twelve months ago when we started, if we were talking about Perth, they often asked where it was in relation to Melbourne or Sydney."

He said part of Perth's appeal was its lower prices for apartments, compared to Sydney and Melbourne.

"We've got fantastic universities in the G8, we've got great weather, good employment, a clean city," he said.

"Perth is more attractive for being in the same time zone ... particularly in the south of China."

Property consultant company Urbis's director David Cresp said overseas investors typically represented about 10 per cent of apartment buyers in Perth.

"We've seen that jump up to about 20 percent in the last couple of quarters," he said.

"Now, whether it remains at that sort of level is yet to be seen over the course of this year."

Projects collapse, are shelved as money dries up

Many analysts said despite higher investment from overseas, some projects would not proceed because developers would be unable to meet their pre-sales targets.

The ABC understands at least four developments have been shelved in the past year and others are unlikely to go ahead.

Mike Enslin, managing director of apartment developer Psaros, believed Perth might soon have an undersupply of apartments relative to demand.

"We are calling a supply shortage to come into the market towards the end of the year as people realise the developments they thought they were buying into aren't going to proceed," he said.

Mike Enslin says the Perth apartment market may face a shortage of supply by the end of the year. ( ABC News: Phil Hemingway )

Psaros has about 450 apartments in its development pipeline, with almost half due to be completed this year.

It has not lowered its prices, but Mr Enslin said the market was very competitive, with incentives - such as whitegoods and wooden floorboards - being offered by some developers to secure a sale.

"All [our] margins have been taken down to the bare minimum," he said.

"Our product will sit at this price until such time as people realise the market's not going anywhere further."

Mr Enslin is also of the view that the bottom of the property cycle has been reached.

"We've probably been there for the last three or four months. As developers, we certainly can't produce our product any cheaper."