Unit owners in Sydney's evacuated Mascot Towers building are facing a bill of at least $10 million to repair the 10-storey building.

Key points: Mascot Towers residents were forced out of the apartment building in June after serious structural issues were discovered

Mascot Towers residents were forced out of the apartment building in June after serious structural issues were discovered The final bill for the repairs is yet to be determined, but residents will vote on an initial plan for a $10 million special levy at a meeting this month

The final bill for the repairs is yet to be determined, but residents will vote on an initial plan for a $10 million special levy at a meeting this month Apartment owners have told the ABC they were "shocked" to find out the new funding arrangement

In a move one resident described as "devastating", the ABC can reveal owners will vote on a $10 million "special levy" to fund "stage one" of the remedial works for the 132-unit block in a meeting later this month.

The Mascot Towers complex in Sydney's south was evacuated in June after engineers spotted cracking in the primary support structure.

It came six months after Opal Tower in Sydney's west was evacuated on Christmas Eve for similar structural problems.

In the minutes of an owners meeting to be held on August 22, owners will be forced to vote on the $10 million levy to fund the works, with the money paid in quarterly instalments over 15 years.

In June Mascot Towers owners voted to raise $1 million for initial works through a similar special levy.

But since that meeting the price tag for the building, which is too old to fall under warranty, appears to have jumped significantly.

Mascot Towers apartment owner Fabiano Dos Santos and his girlfriend Tamiris Coutinho learnt of the funding proposal last night.

Fabiano Dos Santos and his girlfriend Tamiris Coutinho are concerned over the new levy. ( ABC News: Liv Casben )

He said he was "shocked" to find out the new numbers and did not know where he would find the cash.

"Before last night we had this sort of number of $5 million to fix the whole situation so now we're seeing numbers between $10 million and $20 million, [so] we're very confused."

"The numbers are just skyrocketing.

"[It means] we'll probably pay $100,000 per owner, just for this first stage thing."

The Mascot Towers residents' situation has raised questions over liability and exacerbated the "crisis of confidence" in the NSW building industry.

This week the ABC revealed residents of Opal Tower have tabled a class action suit in the NSW Supreme Court against the State Government, while Premier Gladys Berejiklian on Thursday announced a new NSW Building Commissioner to drive "critical reforms".

The State Government has come under fire for failing to properly regulate the industry, with concerns the problems seen in Mascot Towers and Opal Tower are widespread across the city.

A crack in the basement of the Mascot Towers builders. ( AAP: Bianca De Marchi )

Real Estate agent John Higgins represents 12 owners in the Mascot Towers building.

He said his clients were "devastated" with the proposed figure.

"This is a big building and it needs a lot of work to be done," he said. "The levy [will be] a lot of money over the next twenty years.

"I know one of my owners said anything over $40,000 they can't afford and they've been to the banks and the banks won't lend them the money."

At the August 22 meeting, residents will debate a proposal to engage lawyers and a barrister.

The residents will also vote to initiate legal proceedings in the NSW Supreme Court to seek an access order to the neighbouring property, 27 Church Avenue, to investigate "damage to common property".

Under NSW law, building defects are covered under warranty for six years after completion of a development, with experts predicting residents will struggle to find someone to sue.

Like all the residents of the 10-year-old building, Mr Dos Santos and his girlfriend were forced to find a new home after being evacuated in June.

The NSW Government has offered three months of rental assistance, but that is due to run out months before the Mascot Towers is expected to be safe to occupy.

Mr Dos Santos said he was worried.

"This is one of the first times in my life that I don't know what to do."