Australia has built a generation of properties that could become slums in just 20 years, housing and banking analyst Martin North says.

Speaking with 60 Minutes guest reporter, Nine’s Finance Editor Ross Greenwood, Mr North criticised developers and the housing industry for “throwing up” high-rise buildings at such alarmingly fast rates.

He warned viewers that significant defects and safety concerns are imminent.

Analyst Martin North spoke to Ross Greenwood on 60 Minutes. (60 Minutes)

“We have so many properties across Australia which are being thrown up, or have been thrown up, with significant defects in them,” Mr North said.

“I think we've built a generation of properties that frankly could become slums in 20 or 30 years.”

Mr North’s claims come after residents were evacuated from Sydney’s doomed Opal Tower on Christmas Eve last year, when large cracks appeared on the tenth floor and threatened to destabilise the building.

Mr North maintains that the Opal Tower is just one of potentially thousands of buildings that are currently facing, or will soon face, serious defects.

“I wouldn't actually buy in one of the new high-rises,” he told Greenwood.

“I think there are too many risks on the price, on the quality of construction, and other factors too.”

Sydney's Opal Tower was evacuated on Christmas Eve after cracks began appearing in the building.Sydney's Opal Tower was evacuated on Christmas Eve after cracks began appearing in the building. (60 Minutes)

Cracks on the 10th floor skygarden at the Opal Tower. (60 Minutes)

Former NSW Treasury Michael Lambert weighed in on the report, telling 60 Minutes there is a high risk developers and builders are cutting corners in order to get properties on the market as quickly as possible.

“I think you'll find that there's a large number of projects where there are defects occurring… there’s thousands,” Mr Lambert said.

It’s a safety concern that’s compelled him to work towards sweeping reform of the housing industry.

As housing prices fall, more residents of high-rise apartments and suburban homes alike are forced to sell.

Appearing on 60 Minutes in 2018, Mr North predicted a potential 40 per cent fall in house prices – a claim that many believed to be outrageous.

But Mr North stands by his controversial estimates.

“I still think that we could see 40 per cent plus fall over two or three years,” Mr North told Greenwood.

“It’s not going to happen overnight.”

North expects that we will see a 20 to 30 per cent drop in prices , but if international issues continue to grow, his 40 percent estimate is not far-fetched.

“Twenty to 30 percent is my best guess for a local crisis,” Mr North said.

“With international issues flowing in over the top of what's happening locally… [it] will take us even into more negative territory.”

Opal Tower apartment owner Andy Neverly fears he has lost everything. (60 Minutes)

Mr North offered up his predictions of the suburbs and areas headed for crisis, highlighting Sydney’s west as a key problem area.

“I’m seeing Campbelltown and Blacktown, even some of the eastern suburb areas also showing some concerns as well,” Mr North said.

“Areas where the highest number of people with negative equity live, they’re perhaps the areas you would expect. From western Sydney, Baulkham Hills to Mount Druitt.”

In Melbourne, Mr North points to Beaconsfield and Werribee as areas where prices have already begun to slide.

“We are on a downward journey. Prices are not going to rebound any time soon,” he said.