SYDNEY (Reuters) - In their struggle to cool red-hot property prices in Australia’s big cities, authorities are ratcheting up measures that could dent the whole market but avoiding more targeted steps that have had some success in New Zealand and China.

FILE PHOTO: A resident in Sydney's newly-developed beachside suburb of Green Hills walks her dog, February 2, 2015. REUTERS/Jason Reed/File Photo

Australian regulators first focused on reining in investment loans nationally in 2015, by imposing an annual limit of 10 percent on how much banks could expand their investor loan book.

Those steps worked for a while, but the heat is on again in Sydney, where prices are rising almost 20 percent a year, having more than doubled since 2008, and Melbourne, where the pace is over 15 percent, according to property consultant Core Logic.

That and all-time high household debt prompted the Australian Prudential Regulatory Authority (APRA) to move again on Friday, asking banks to limit new interest-only loans to 30 percent of total new mortgage lending, from 40 percent now, and promising a lot of “monitoring”, “scrutinising” and “observing”.

Industry players doubt that will do the trick.

“I personally don’t think this will have a material impact,” said Simon Orbell, director at Sydney-based mortgage broker Smartmove, as prices kept rising even though it was already a tough lending market.

“Maybe more needs to be done,” he added.

Behind-the-scenes pressure has already led the major banks to raise rates on investment loans, particularly for interest-only products favored by speculators, according to sources with knowledge of the situation.

Variable interest rates on investor loans from Commonwealth Bank of Australia CBA.AX - the country's top mortgage lender - are as high as 5.94 percent, compared with 5.25 percent for owner occupiers and an official cash rate of 1.5 percent.

There has been market speculation that the Reserve Bank of Australia will be forced to hike interest rates, a yet blunter instrument, though record low inflation and weak wages growth make that an unattractive option.

There is also political resistance to measures that could make prices actually fall, with two thirds of households owning their homes.

The uneven nature of the market means such measures, even if they cool the hotspots, can cause collateral damage elsewhere.

“There is no one national housing market in Australia. So, what may impact in Sydney in one way can impact exactly the reverse in Perth,” explained Treasurer Scott Morrison.

“So, the use of big-stick, sledgehammer-type changes, one must be very cautious of that, because it can have quite negative impacts in markets.”

TARGETED RESPONSE

Neighboring New Zealand had been grappling with a similar problem in Auckland until its central bank asked lenders to seek a greater deposit for home loans just in that city.

The tactic seems to have worked. The explosive Auckland market has cooled since last September, with sales volumes at their lowest levels in at least five years, according to the latest data from the Real Estate Institute of New Zealand.

In China, the solutions are tailor-made to the locality, with some cities requiring deposits of 40 percent or more, others putting limits on how many homes an individual can buy or barring non-residents from buying.

More recently, the Reserve Bank of New Zealand (RBNZ) has been lobbying the government to get permission to add debt-to-income (DTI) limits to its macroprudential arsenal aimed at combating the brisk pace of home prices.

“DTI policies can increase the resilience of households to income shocks, reducing the number of forced house sales in a downturn,” the RBNZ said in March. Together with loan-to-value restrictions, the RBNZ said it hoped to achieve “a more targeted response to rising house market risks”.

That remains just a proposal for now, however.

“There hasn’t been any real political appetite or enthusiasm for DTIs,” said Christina Leung, senior economist at the New Zealand Institute for Economic Research. “There’s a lot of uncertainty as to ... what it would do to house prices.”

In Australia, such policies won’t wash, said John Hewson, professor at the Crawford School of Public Policy, Australian National University.

“We have had a long history of deregulating our financial system, so there is a strong reluctance to start regulating banks with lending restrictions or interest rate caps,” said Hewson, a former leader of the ruling Liberal Party.

Regulators are also worried about the risks from a slowdown in the home-building boom. According to official estimates, every A$1 spent on residential construction generates A$1.31 worth of spending elsewhere in the economy, and every A$1 million creates 17 full-time jobs.

And unlike in China, Australians still largely expect government to let the market take its course.

"They should ... just sit in a corner and not do a thing," said Lindsay Partridge, managing director of Brickworks BKW.AX. "Any of the things that they do are going to affect confidence, and that is going to affect construction activity ... The state governments should release more land for construction and just let the market run and correct itself."

For graphic on the property market in Australia and New Zealand click