An engineer overseeing the construction of a major urban hub being built in Sydney is under investigation over "structural issues" in a previous project.

Engineers Australia, the industry's peak professional body, is probing Anthony Hasham after receiving a complaint from NSW building commissioner David Chandler in May.

It's the first time NSW's construction watchdog — which was handed sweeping powers to clean up the building industry last year — has referred an engineer to the organisation.

Mr Hasham's company, Australian Consulting Engineers (ACE), was responsible for overseeing the construction of the Skyview apartment complex in Castle Hill in Sydney's north-west.

The high rise was hit with a prohibition order in June after a team of inspectors from NSW Fair Trading reported finding "the existence of structural issues that would require specialist engineering advice" in the basement of two of the five proposed towers.

The Skyview complex is one of Sydney's biggest residential property developments with around 960 apartments.

Two of the project's five towers are now complete, with the remainder still under construction.

Buyers were recently prevented from moving into the completed towers for several weeks until the order was lifted after developer Toplace agreed to be liable for any potential future "defects" for 20 years.

Developer Toplace didn't respond to questions from the ABC, but company director Jean Nassif has previously said consumers could be confident in the building.

"Four engineering groups — including a panel of three independent professors of engineering — have studied the basement structure for compliance with the Australian Standard and Building Code of Australia, it has passed with flying colours on each review," he said.

Engineers Australia said if the complaint against Ms Hasham was upheld, he could be stripped of his accreditation.

"Sanctions could include a written warning or reprimand, suspension or cancellation of their membership, or removal of the member's title," a spokesperson said.

Mr Hasham denies any wrongdoing.

He is listed as a chartered professional engineer on the National Engineers Register (NER).

Reaching chartered status assures "the world you are dedicated, reliable and top of your industry", according to Engineers Australia.

However, a spokesperson for the professional body noted if Mr Hasham's accreditation was removed it would not stop him practicing, only impact his ability to attract future clients.

NSW Building Commissioner Mr Chandler said it was now up to Engineers Australia to act.

"It is important that industry associations also hold their members to account and consider potential breaches of their Code of Conduct," he said.

It's also understood if Mr Hasham lost his title, he may struggle to re-register with the NSW government.

Compulsory registration of engineers that work on multi-storey residential apartment complexes was launched in July and is one of a range of measures introduced after extensive building reforms were passed in NSW Parliament last year to try to avoid a repeat of Sydney's Mascot and Opal tower fiascos.

Mr Hasham said he was aware of the complaint against him but not concerned about losing his accreditation.

"I wish to note that an investigation or an allegation made does not in itself result or equate to negligence or guilt," he said in a statement.

"I deny any wrongdoing.

In June this year, Mr Hasham was honoured with a medal of the order of Australia (OAM) for his service to business and Australia's Lebanese community.

His latest project, the Box Hill City Centre, is the centrepiece of a major transformation taking place in the area bordering Rouse Hill in Sydney's Hills District.

Once fully developed, the suburb of Box Hill is predicted to attract around 250,000 new residents, according to Toplace.

More than 680 apartments in Box Hill City Centre are expected to begin selling off the plan soon.

The $226 million, nine-storey City Centre project will also include a large shopping complex and is expected to be completed in early 2023.

A spokesperson for the Hills Shire Council said it would not send extra inspectors to review the project, as developer Toplace had its own private certifier.