Sydney: All 300 residents of the brand new Sydney apartment building that developed a crack on Christmas Eve will be re-evacuated for up to 10 days so the construction company can conduct further investigations and repairs.

Opal Tower in Sydney’s Olympic Park was evacuated on Monday night after a crack developed in a load-bearing concrete panel and the building shifted 2mm — causing plaster to crack and doors to stick in their frames.

On Tuesday the building was declared safe to live in by its developer, Ecove, and residents of two-thirds of the tower were told they could return to their apartments.

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

But on Thursday afternoon Icon announced that all residents would now be relocated from the building so the entire site could be investigated and repaired.

All residents would be moved within 24 hours and the work could take up to 10 days, a spokeswoman said.

But the company stressed that the building was still structurally sound and no residents were in danger.

“The temporary relocation is a precautionary measure to allow engineers to work around the clock to investigate and remediate the site in the quickest time possible,” a statement said.

“The damaged section of the building has now been reinforced as a precautionary measure while a team of engineers carries out the investigation. The thorough investigation is being led by global engineering firm WSP, with assistance from senior engineers from Kajima Corporation.”

Kajima Corporation is a Japanese construction company that is the majority owner of Icon.

Since Tuesday morning most residents of Opal Tower’s 392 apartment have been allowed to return home. But 51 units, located in one corner of the building, were still blocked off.

Dave, a resident of an affected unit, told Guardian Australia on Tuesday he had been given five minutes on Christmas Day to return and collect his belongings.

“My apartment and my neighbour had notices on the doors that said you can’t actually live in here,” he said. “Nobody else was affected, it was just that corner.”

Icon said all affected residents would be compensated for the disruption.

Also on Thursday, the New South Wales planning minister, Anthony Roberts, announced that two engineering professors would lead an investigation into what had happened to the building.

Earlier experts had said problems with apartments like Opal Tower had been “brewing for a long time” owing to a poor compliance system in New South Wales, overdevelopment and a “she’ll be right” attitude to construction.

But Bassam Aflak, Ecove’s director, rejected this: “Any suggestion the building damage pointed to ‘a broader pattern in the industry’ is completely wrong. The city’s ‘development boom’ has not led to cutting of corners. There has been no cutting of corners.

“It’s too early to leap to any conclusions, for instance, to speculate on wider building issues because of what appears to be one failed panel.”

Aflak also said on Wednesday that the evacuation had only made news because it occurred during Christmas.

“The media has understandably investigated this as a sensational story but it’s happened over the Christmas break when there is a scarcity of people who can comment with authority,” he said.