'Not a simple fix': Cracks in basement investigated after Sydney tower evacuated

For the second time in six months, a Sydney high-rise apartment complex has been completely evacuated due to cracking and reports of movement.

Residents from all 122 units in Mascot Towers and nine units in surrounding buildings were unable to sleep in their own homes after concerns about the structural integrity were raised about 6pm on Friday.

"There has been some concern with movement in the building," Fire and Rescue NSW Superintendent Adam Dewberry told AAP.

It's the second such mass building evacuation in Sydney since December, when cracks appeared in the newly-built Opal Tower in Sydney Olympic Park.

Mascot Tower residents were evacuated on Friday night. Pictured is the building in Sydney's south.
A Sydney apartment block in the southern suburb of Mascot has been evacuated. Source: 9News

A Fire and Rescue NSW spokesman on Saturday said there were no concerns the decade-old Mascot Tower could collapse and the evacuation had only occurred as a precaution.

The cracks in the basement which had been monitored over some time became worse on Friday, he said.

The call to allow some residents to stay overnight in the tower was rescinded late on Friday as they would have been forced to enter and exit the building only through fire exits, he said.

A temporary shelter was established at Mascot Town Hall as residents wait for the 'all clear', police say.

"It will be a process. It won't be a simple fix, it will be very methodical," Supt Dewberry said.

A photo of cracks inside a business at Sydney's Mascot Towers.
Cracks inside the building at Mascot Towers. Source: 9News

The building manager, Building Management Australia, has been contacted for comment.

Some units in Sydney Olympic Park’s Opal Tower are still uninhabitable as permanent structural remedial works continue.

An independent report released in February found critical support beams were left susceptible to "bursting" because they were under-designed and some were made from lower strength concrete.

The tower was found to be structurally sound overall but having several structural and construction issues.

The tower's builder Icon is continuing to reimburse affected owners for rental loss but in May stopped covering costs for tenants' alternative accommodation.

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