ANZ has made home ownership in WA's boom-or-bust mining towns extremely difficult, with prospective buyers in the Pilbara and Goldfields now forced to cough up a 30 per cent deposit.

The Australian dream has never looked so unattainable under the new policy, forcing buyers to find $225,900 for a deposit on an average-priced home in the iron ore hub of Port Hedland.

A deposit of $102,900 would be needed in Australia's unofficial gold capital of Kalgoorlie-Boulder.

ANZ is the first of the traditional "big four" banks - alongside Westpac, Commonwealth Bank and National Australia Bank - to implement the policy.

The hit list covers other mining regions, including the birthplace of BHP Billiton at Broken Hill in NSW, and South Australia's Olympic Dam and Roxby Downs.

It comes in the same week Federal Treasurer Joe Hockey sparked criticism when he told first-time buyers struggling to afford a house to get "a good job that pays good money".

Barely a month after posting a $3.5 billion first-half profit, ANZ yesterday said its changes to home loan lending criteria reflected the "localised downturn in a small number of towns dependent on the mining sector".

The new policy has shocked real estate agents and mortgage brokers, who operate within the industry standard of five to 10 per cent deposits.

Loans via the State Government-backed Keystart require a 2 per cent deposit.

One broker, who spoke on condition of anonymity because he did not want to jeopardise his business relationship with ANZ, said the "crazy" policy would "price ANZ completely out of the market".

Real Estate Institute of WA deputy president Hayden Groves said banks were likely to "tighten up" in riskier markets because mining towns were reliant on resources investment and prone to "savage swings".

"It's alarming that this is one of the 'big four' banks and you do worry if this is the thin edge of the wedge and other banks may follow suit," he said.

"There are still plenty of lenders out there but you may be forced to go with a fringe lender and interest rates which are not as attractive."

The iron ore price collapse has seen thousands of job cuts in WA's north and resulted in a "bloodbath" for Karratha's property market.

REIWA figures showed the average house price in Karratha tumbled 34 per cent from $680,000 to $450,000 in the 12 months to March 31.

Newman was down 13 per cent to $680,000 and Port Hedland 11.4 per cent to $753,000.

Gold has retained some of its lustre to ensure Kalgoorlie-Boulder remained stable with a 0.1 per cent fall to $343,000.

ANZ is the only bank with branches in the mining towns of Kambalda and Norseman, where the median house price is $125,000 and $33,000 respectively.

Ray White Kambalda principal Cheryl Davis described the ANZ policy as "another kick in the teeth" for the town, which has been hit by about 140 job cuts in the past two months.

"People just don't have that sort of money in their back pocket," she said.

"Their best bet now will be going through a broker.

"As soon as they (ANZ) realise they won't do any house loans, they will have to rethink that."

She views the State Government's decision to cut the $3000 first-home buyers grant for established homes as another blow.