An inquiry began on Monday into the regulation of building standards, quality and disputes in NSW, after a series of incidents involving damaged unit buildings.

Residents of the Mascot complex's 132 apartments have been forced to stay elsewhere since the building was evacuated in mid-June due to cracking in the primary support structure and facade.

Apartment owner Vijay Vital broke down as he told the NSW upper house inquiry the situation had devastated his family.

"I stand here as a parent ...my daughter asked me 'When can I go home?'" Mr Vital said.

Mascot Towers has high strata fees compared to neighbouring buildings and had been plagued by defects due to substandard materials and negligence, he alleged.

"This has caused a lot of trauma in the past two months because we were evacuated, the reason for which we don't know," he said.

"We have insurance but we can't claim any of it until we know the root cause."

Fellow owner Alton Chen said for a lot of Mascot residents their apartment was "the only place we call home".

"We don't know when we can go back, we don't know how much we need to pay for in the future," Mr Chen told the inquiry.

He said without the state government's assistance package a lot of owners would be paying for "mortgages for a place we can't live in" and the cost of alternative accommodation.

Department of Customer Service' executive John Tansey couldn't say exactly when the new Building and Development Certifiers Bill - which was passed in October 2018 - would come into effect.

The legislation will give the government compliance and enforcement powers, the right to suspend or cancel a certifier's registration and allows for substantial fines for body corporates who don't have sufficient insurance.

"I don't want to quote an ad-hoc date, we need to develop the regulations, we need to get those right in consultation with industry," Mr Tansey told the inquiry.

Greens MP and committee chair David Shoebridge replied: "You'd understand the frustration that legislation that was hurried through parliament ... is still not in effect."

In a submission to the inquiry, the Mascot Towers Owners Corporation, said owners and residents relied on the system but the NSW government had failed to establish a sufficiently tough regulatory framework for builders, certifiers and property developers.

There'd been a failure of the private building certification process, a lack of supervision over builders and an unfair burden on owners to rectify defects.

The submission outlined Mascot Towers' various defects leading up to the cracking problem, including lukewarm water all year round, severe stormwater flooding and the incorrect use of electrical cables.

The building was passed for occupation despite these faults, it said.

"Our residents have inherited a building with numerous defects ... which were originally signed off on by our government, engineers and certifiers as 'within standards'.

"Somewhere along the line, maximising profit has become a misinterpretation for 'delivering quality'."

The group said NSW should fund repairs to Mascot Towers as the defects "happened under the watch of government".

David Chandler, appointed this month as the inaugural NSW building commissioner, will start in his new role later this week.

Australian Associated Press