Three residents inside Sydney’s Opal Tower have refused to evacuate as the New South Wales government announces a crackdown on building certifiers.

Residents of the new Sydney apartment building were evacuated after a crack was found in a pre-cast concrete panel on Christmas Eve.

Some were initially allowed to return but were then re-evacuated on Thursday so that the construction company behind the building could conduct further investigations and repairs.

At a press conference on Sunday, the planning minister, Anthony Roberts, revealed that three residents had refused to leave the building. He said the residents were in “parts of the building that aren’t affected by this”.

“They have their own individual reasons why they don’t wish to leave and I must say public works engineers on the first night decided the building [was] safe for habitation, structurally safe in those areas,” he said. “Those people are away from those areas of concern.”

The state government has announced its own investigation into the crack and on Sunday the minister for better regulation, Matt Kean, announced he would also introduce new legislation to address “dodgy certifiers” in the industry.

“There has been growing community concern about dodgy certifiers and, while the cause of the recent problems at the Opal Tower remains unknown, what’s happened there has put a spotlight on the industry again,” he said.

Kean announced a new compliance policy that would see certifiers found to have negligently signed off on an unsafe or structurally unsound building immediately kicked out of the industry.

Certifiers who are found to have breached the industry’s code of conduct on building quality will also be banned from working on new strata developments for 12 months.

He also announced a new “name and shame register” that would make a certifier’s disciplinary record available to the public.

The debacle surrounding the Opal Tower has led to a wave of recriminations.

On Boxing Day, the director of the building’s developer, Ecove, hit back at what he described as “sensational” reports, declaring that the Opal Tower was a “high-quality” building and the company that built the tower, Icon Constructions, was “a well-established, high-quality builder”.

Bassam Aflak claimed the issues with the building had only become a news story because “it happened over the Christmas break”.

But the NSW Labor opposition has sought to turn the evacuation into a political issue. On Sunday the opposition leader, Michael Daley, announced his own plans to lift building standards and protect home buyers, and criticised the government’s response to the issue.

“For eight long years this government has done nothing except let the building industry drift,” he said. “They’ve let the cowboys come in and now today they’re saying they’re going to act – not because it’s timely but because they want to save their own bacon.”

On Saturday the developer said some residents would need to be moved from their temporary hotel accommodation over New Year’s Eve as their rooms had been previously booked out for the celebrations.

Roberts said that everyone who needed accomodation had been provided with a similar replacement.

“The developer and builder have ensured that every person that has been moved from that building has and will continue to have accommodation during this period,” he said.