Booming Sydney property prices are showing no signs of slowing, according to the latest private research.

Key points: Sydney property prices grew 11 per cent in 2016

Sydney property prices grew 11 per cent in 2016 Investment analyst says Sydney-siders have taken on a 'record amount of mortgage debt'

Investment analyst says Sydney-siders have taken on a 'record amount of mortgage debt' Other cities around Australia are showing property price fatigue

Data from number-crunching firm Moody's Analytics points to strong price growth in 2016, and then more to come in 2017.

Moody's economist Emily Dabbs said Sydney property prices had grown 11 per cent in 2016.

"When you look at the chart of the price growth it's just up, up, up and up," she said.

"We haven't really seen a significant decline in prices in Sydney for quite some time, and it's very unlikely to be that way, just because of the amount of demand that there is in the city."

Ms Dabbs said Sydney was in a league of its own.

"Interest rates are quite low, and that tends to provide a bit of a boost more to your eastern states of Sydney and Melbourne where income growth tends to be quite high," she said.

"You're also seeing a lot of population growth in Sydney and Melbourne, especially given the job market tends to get quite a pull factor to there."

'Huge debts held by Sydney-siders should not be ignored'

But Moody's forecasts have been criticised by one investment analyst.

Roger Montgomery, who runs the Montgomery Fund and manages over $1 billion worth of client funds, said the extraordinary amounts of debt Sydney-siders had taken on could not be ignored.

"People have taken on a record amount of mortgage debt, compared to income and compared to GDP, to chase higher house prices, particularly apartments," he said.

"In response to that, there's been a record supply of apartments coming onto the market.

"Now, you can't have record-high prices and record supply co-existing for very long."

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Mr Montgomery said there were already signs developers were finding it harder to find enthusiastic buyers.

"They will be forced to discount their apartment prices in order to move the inventory," he said.

"We're already seeing that start, and we've seen some apartment developers offering frequent flyer points, we've see others offer holidays, and yet others offer 10-year rental guarantees.

"That's a form of discounting."

Other cities starting to cool down

While Sydney continues to boom, other cities around Australia are already showing property price fatigue.

Melbourne prices are forecast to stagnate over the next few years.

Moody's said slower growth in apartment values compared with detached houses showed buyers were already pricing in expected increases in supply.

Brisbane's home values are also set to cool as unemployment edged higher.

Ms Dabbs said the mining downturn continued to weigh on housing markets in Perth and Darwin.

Prices in Perth are not expected to pick up significantly until the 2020s.

"The unemployment rate in Perth, for example, is quite high compared to the rest of the country," Ms Dabbs said.

"That's really hampering any income growth and making it difficult for households to pay higher prices for houses."

Mr Montgomery warned that the downwards pressure on property prices on the west coast would ultimately make its way to the east coast.

"The west coast of Australia was the first part of the pond to be affected by the pebble that was dropped in China when economic growth slowed," he said.

"I suspect that ripple is moving across the Nullarbor and will eventually hit the east coast as well."