German supermarket giant Aldi plans to open four stores in Perth in the next two months, in a move one analyst says will force down prices in the state.

Aldi said it would open supermarkets in June in Mirrabooka Square, Kwinana, Belmont and Lakeside Joondalup.

The company said it would have 20 stores opened by the end of the year.

"This is an exciting time for the Aldi business and for West Australian shoppers," managing director Damien Scheidel said in a statement.

"The first stores form part of Aldi's long-term expansion plans, which will see up to 70 stores developed around Western Australia and 1,200 permanent jobs at Aldi."

Perth-based retail analyst Barry Urquhart said consumers had been paying far too much for groceries in Western Australia.

"Supermarket prices [in Western Australia] have been higher," he said.

"Fruit and vegetables offer retails a profit margin of somewhere between 150 and 300 per cent.

"So consequently there has been a premium that has been paid by West Australian consumers.

"The evidence shows that when Aldi opens a supermarket in the eastern states of Australia retail prices across the board in packaged goods, fruit and vegetables, in the immediate area go down by 6 per cent.

"So you can be rest assured that consumers are waiting and will be advantaged by the arrival of Aldi."

Aldi said it had hired 500 people so far including 45 store managers and 342 trainee store managers and retail assistants.

The company has vowed to offer high-quality products equivalent to market-leading brands at lower prices.

It said while 90 per cent of its groceries were own-brand, the majority of these were Australian-made.

Aldi also plans to open stores in Armadale, Australind, Butler, Camillo, Cannington, Ellenbrook, Halls Head, Harrisdale, Haynes, Lakelands, Maddington, Mandurah, Mundaring, Nedlands, Rockingham, Secret Harbour, South Lake, Southern River, Waikiki and Wattle Grove.