New laws granted to the NSW Building Commissioner will allow entry to any apartment or free-standing home under construction as the government cracks down on shoddy builds.
The commissioner's role was created in 2019 by the former coalition government in an attempt to restore confidence in the building and construction industry.
Labor Premier Chris Minns says the industry still needs tighter regulation, and has boosted the powers of the commissioner and allocated another $24 million to help.
He says Australia's housing crisis is leading to a major push to build, and quickly, but NSW won't compromise on quality.
"Home buyers in NSW can be confident that we've got a tough cop on the beat in the building industry, ensuring that they can have confidence in the quality of the home they're buying," he said.
"We don't want to see a situation where young people in particular waste their life savings on shoddily built housing in this state. Those days are over."
Current laws only grant access after a home is completed, and a formal complaint lodged.
Commissioner David Chandler told reporters his job now was to work with the industry to improve standards, build capability, and capacity.
"So, that's not just simply the big stick, that is what can we do to get down and work with the industry to raise its competencies," he said.
Mr Chandler said the NSW industry needed another 50 builders and developers entering the sector every 12 months.
Minister for Better Regulation and Fair Trading Anoulack Chanthivong said supercharging the regulator's power would give confidence to people building a home.
"There is no room in this state for rip-off merchants taking home buyers for a ride," he said.
"Grifters in this sector will have nowhere to hide in NSW."
The boosted powers mean the commissioner can now uncover defects before completion and compel builders to get them fixed.
The government is also cracking down on builders who rebrand to avoid liabilities, by cancelling or refusing licences.
The building supply chain will face more scrutiny, to prevent poor materials reaching sites in the first place, and 400 inspectors from Fair Trading will be moved over to the Building Commission.