Residents of the cracked Opal Tower in Sydney will be forced to spend more time outside of their homes after an interim report revealed damages that need major rectification work, as well as a number of issues with the property’s design and construction.

Anthony Roberts, New South Wales planning minister, said the question of whether residents should return to their homes was beyond the scope of the report, but Professor Mark Hoffman from the University of New South Wales advised residents to wait.

This is despite Icon, the builder of the tower, declaring on Friday that it was safe for residents to go back home over the weekend.

The interim report, which was released more than three weeks after the fiasco, found that while the building is not in danger of collapsing, it has many construction defects.

Hoffman and Professor John Carter, authors of the report, focused on levels 3, 4, 9, 10, 16 and 26 of the building and found hob beams on levels 4 and 10 to have major damage.

Hoffman and Carter’s investigation was also able to identify that some parts of the building did not follow the design drawings or expected standards.

The severely damaged hob beams on Level 10 and Level 4, for instance, had bearing capacities that indicate factors of safety lower than required by standards, according to a report by au.

In addition, some precast concrete panels measured 200mm wide, instead of 180mm, and a series of reinforcing bars were found to be 20mm, instead of 28mm.

The report revealed significant issues concerning the property, but there were no definitive conclusions about what caused the damage in the new apartment building.

“While we have isolated the probable cause to localised structural design and construction issues, we need more information to make definitive conclusions about the cause or causes of the damage to this structure and the proposed rectification,” Hoffman and Carter said.

Roberts said that more reports would follow and the latest findings only make up an interim report.