Ongoing problems with the troubled Mascot Towers apartment building could see the repair bill blow out to more than $50 million, leaked emails reveal.

Key points: Initial estimates put the repair bill at $7 million but that's blown out to $32 million plus

Initial estimates put the repair bill at $7 million but that's blown out to $32 million plus An extra $21.5 million in interest on a 15-year loan will bring the final bill to $53.5 million

An extra $21.5 million in interest on a 15-year loan will bring the final bill to $53.5 million One apartment owner says the developer has gone into liquidation and can't be held responsible for the bill

Mascot Towers, in Sydney's south, has been plagued by structural issues and cracking since the complex was evacuated almost a year ago.

Now, owners are considering selling the beleaguered development.

Residents were evacuated when significant cracks were discovered in the building's primary support structure last June, and are still yet to return.

Initial estimates put the repairs at $7 million, which would be funded by a special strata levy.

But the price tag subsequently blew out to $15 million, then $25 million, before this week's estimate of $32 million for rectification works.

A further $21.5 million in interest on a 15-year loan would bring the final bill to $53.5 million.

That is around $10 million more than previous estimates, and equates to an average of about $400,000 for each owner of the 132 units.

Treacy Sheehan owns a three-bedroom penthouse in the complex and expects to pay an additional $5,000 a month towards the repairs.

"That's on top of strata fees, mortgages, utilities — we'll all go bankrupt at this rate," she said.

Cracks in the building's facade have contributed to an increase in the cost of repairs. ( ABC News )

A confidential email, obtained by the ABC, was sent to the building's owners on Wednesday night by the Strata Committee.

It provides a breakdown of the new costs and concedes they are significantly higher than initial estimates.

In the email the Strata Committee blamed recent problems with the building's facade for the increase.

"As an indication of how the costs have continued to mount, a total of $3,880,000 has been allocated for the facade repair," the email said.

Apartment owner Brian Tucker, who is on the Strata Committee, said owners would be asked to consider a collective sale.

He conceded Mascot Towers would likely only sell for its land value.

"But what do we do?" he said.

"Do we try to get rid of it but go into debt for the rest of our lives … or keep throwing money into it but find more and more faults?"

"It's a lose-lose situation. We have to try and find the least-worst option."

Mr Tucker said the building's developer had gone into liquidation and was unable to be held responsible.

The NSW Government is covering rent for displaced owners and residents as rectification works continue and has launched an inquiry into building standards after a series of faults emerged in buildings across Sydney.

But owners of Mascot Towers apartments want immediate help, and have been warned to brace for more bad news.

"There is no guarantee that further issues will not be identified in other areas of the building and we can only address them as they arise," the Strata Committee email read.

The problems at Mascot Towers followed similar issues with the Opal Tower at Sydney Olympic Park, which had to be evacuated on Christmas Eve in 2018 after several major cracks were found.