NATHAN Birch’s mum still lives in his childhood home in Mt Druitt.

The Sydney investor, who now owns more than 200 properties and claims a net worth of $55 million, started with his first purchase at the age of 18, just around the corner.

Appearing on Channel Seven’s Sunday Night program, Mr Birch and his mum sat down for a lamb roast with reporter Denham Hitchcock, who asked why, with all that money, he hadn’t bought his mum a mansion. “Because mum doesn’t want one,” she said. “My little house is fine, that’s what I always say.”

Mr Birch added that as his mum got older, he planned to build his large “dream home” where she would live with him. “Then I can get food like this cooked every day,” he said.

The 20-minute profile, which features Mr Birch taking a helicopter ride over the Gold Coast to survey his empire of properties — some of which have doubled in value since purchase — comes at a difficult time for his style of investing.

Mr Birch’s business, which he runs with fellow investor Daniel Young, guides young Aussies through the same process he used to make it big — channelling equity from capital gains into deposits for new purchases, a technique which some critics describe as risky.

Last year, a crackdown by Australia’s financial regulators on interest-only and investor mortgages forced the banks to impose stricter lending criteria. Unable to come up with higher deposits or service higher interest payments, many investors bowed out of the market.

That partly contributed to a housing correction which started in the second half of 2017, with national dwelling values slowing in October before turning negative in December.

Owning multiple, highly leveraged properties can quickly go south if interest rates rise.

While banks have already raised rates on interest-only and investor mortgages, the Reserve Bank has not touched the official cash rate since August 2016. Most experts don’t believe the cash rate will move until at least the end of this year, if not later.

Mr Birch said he wasn’t worried. “I believe interest rates are [here] to stay,” he told Sunday Night. “Look, I’ve heard lots of these scenarios. Going back in 2003 when I signed my first contract I was shaking, I thought the same things myself. We’re not a Detroit, we’re not America, and our systems are heavily regulated to protect ourselves from that.”

Telling the program his 200 properties were “not enough”, Mr Birch said he believed the best place to buy was the Gold Coast. “The market here I think is only just scratching the surface,” he said. “It’s like Australia’s Miami. Prices are still post-GFC prices, still very low.”

The Sunday Night segment also features two of Mr Birch’s young clients, 26-year-old Rochelle Ryman and 23-year-old Ozkan Dagdasandara, who have purchased their first properties on salaries of just $65,000 and $50,000 respectively.

“It’s like my hard work has paid off. I feel rewarded for my sacrifices,” said Ms Ryman, who has moved back in with her parents to save money. “My weekly budget for my groceries, all my food, everything is $30. If I spent over $150 in one week I’d be feeling pretty sick.”

Mr Dagdasandara, who sold his beloved Nissan Skyline to come up with a deposit for a $250,000 plot of land outside Newcastle, said he could be out travelling the world and spending but “at a certain point you realise time flies by”.

“And then what, you’re 25, 27, 30, no family, no kids, no lifestyle, there’s no foundation to say this is who you are,” he said.

It came as Mr Birch, who last year revealed he was selling up some of his massive portfolio due to tightening finance conditions, hit back at a report which suggested he was struggling to meet his mortgage payments.

The Australian Financial Review reported earlier this month that Mr Birch had been sued by his lender, Permanent Mortgages, after defaulting on a $535,000 high-interest mortgage for a Gold Coast investment property.

Mr Birch said the AFR story was “currently with the lawyers for misrepresentation”.

“To confirm, I never got sued, the property never got repossessed, and the situation was that I had an overdue amount which equalled to one month’s interest which was paid immediately as soon as it came to my attention,” he said.

“Having 200-odd properties, the admin side of things can become a bit too much and not seeing the mail on time meant I had no idea of this.”

Sunday Night airs on Channel Seven on Sunday 14 January at 7:00pm