Millions of Australians have profited from the mantra that house prices only ever go up. But is that shibboleth about to be demolished?

Certainly, most of the experts the ABC has spoken to are not expecting the kind of double-digit price growth in 2017 that Sydney and Melbourne have experienced for much of the past five years.

NAB's latest quarterly residential property survey — based on interviews with around 250 industry participants — is tipping average capital city house price growth of 3.4 per cent, with units expected to lose 0.8 per cent in value this year.

The bank's chief economist Alan Oster said its housing price forecasts were revised upwards, from +0.4 and -1.6 per cent for houses and units respectively.

"Solid market sentiment in the NAB survey and a surprisingly strong price response to lower interest rates in 2016 has prompted us to revise up our 2017 forecasts, given NAB's expectation for more rate cuts this year," he noted in the report.

"However, we still expect the housing market to cool noticeably in 2017, especially for apartments."

NAB home price forecasts (%) 2013 2014 2015 2016 2017 Sydney (houses) 15.2 13.4 11.5 16.7 4.5 Sydney (units) 11.6 8.3 11.3 9.6 1 Melbourne (houses) 8.5 8.4 11.7 15.1 5.6 Melbourne (units) 8.7 1.1 6.9 1.7 -2.7 Brisbane (houses) 5.3 5.2 4.3 4 1.7 Brisbane (units) 3.5 1.2 1.8 -0.2 -1.8 Adelaide (houses) 3 4.5 -0.3 4.5 1.5 Adelaide (units) 0.6 2.5 1.4 1.1 0.7 Perth (houses) 10.2 2.1 -3.8 -4.4 -2.7 Perth (units) 6.3 1.9 -3.5 -3.2 -3.8 Hobart (houses) 2.9 3.3 -1.6 11.7 3.5 Hobart (units) -5.1 5.9 8.6 6.7 0.6 Capital city avg (houses) 9.9 8.4 7.8 11.6 3.4 Capital city avg (units) 9 5.1 7.9 5.9 -0.8 Source: NAB Economics, CoreLogic

Far from being a downbeat prediction, NAB's forecast is more optimistic than those of many experts.

'Pessimistic outlook' across Australia

Economic forecasting agency BIS Shrapnel's managing director Robert Mellor said stagnant or moderately falling prices were his base case for the next three years.

"Will there be a correction in prices in '17, maybe into '18? Yes — our view is actually quite pessimistic on the outlook for house prices across Australia," he told the ABC's Business PM program.

"BIS Shrapnel forecasts the strongest house price growth will be in Hobart and Canberra over the next three years, but even there the rises are tipped to be between 10-15 per cent, or less than 5 per cent per annum."

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As for the big markets, Mr Mellor said he saw Sydney house prices flat to down a couple of per cent over the next few years, while apartment prices could drop 4 or 5 per cent, with possible falls of up to 15 per cent for some units in Melbourne and Brisbane.

It is a view that fits with the outlook of economist Stephen Koukoulas.

A prominent social media advocate for young people to jump in and buy a home, Mr Koukoulas nonetheless expected that the next couple of years may see home prices decline.

"We might have a year, perhaps two, where prices are weaker, softer, down a little bit even," he said.

"I don't think the problem will be there unless we have a really strong rebound in dwelling construction in the next six months."

Of course, there are those predicting something far worse.

Professor Steve Keen — famous for his trek up Mt Kosciusko after losing a bet with a fellow economist that house prices would crash during the global financial crisis — is expecting his prediction to come true eight years on.

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"I think we're really reaching [debt] saturation level and, once you're at saturation, you no longer have house price growth because you no longer have mortgage credit growth," he argued.

"So we're approaching the same problem that Ireland hit, that Spain hit, we've just delayed it for eight years by borrowing more money."

Despite forecasting moderate prices falls, Mr Mellor was adamant "we certainly won't see a crash".

"To get a crash, we would either need to see a substantial rise in interest rates or a significant rise in unemployment, and I think either of those two things are very unlikely," he said.

2017 price surge could come with 2018 crash: SQM

Interestingly, one of the most optimistic home price forecasts for 2017 comes with the large caveat of a potential crash in 2018.

That forecast comes from SQM Research, which is predicting 11-16 per cent home price growth in Sydney and 10-15 per cent in Melbourne next year.

"What we have noticed in very recent weeks is an acceleration, particularly in the Sydney housing market," he told the ABC in November, when the forecast was released.

"Our view is that this acceleration will continue, it will go well into 2017."

NSW stamp duty revenues surged in November and December 2016. ( Supplied: RBC/Office of State Revenue )

It is an opinion backed by the latest stamp duty revenue figures from New South Wales for November and December, which showed an 18 per cent jump in transfer duties as more homes changed hands at higher prices.

The downside of this rampant home price growth is the growing likelihood of a bubble that could burst catastrophically.

Mr Christopher argued that the Reserve Bank and APRA (the bank regulator) should move early this year to counter the resurgent boom.

"If there is no action, it could be a large issue in 2018 where potentially a hard landing could play out," he warned.

Given that Australian housing remains among the least affordable in the world, according to Demographia's latest annual report, it would seem logical that the nation's booming markets must cool soon or face a bust.

If Australia's two biggest housing markets of Sydney and Melbourne did collapse, there is no way the nation's economy and financial system could escape the fallout.