Former Auburn deputy mayor Salim Mehajer has taken the stand at his own bankruptcy appeal hearing, revealing he has plans to borrow as much as $82 million for five property developments in Sydney's western suburbs.

In a hearing which ran well into the night, the appeal also heard the disgraced property developer owes the Australian Taxation Office $8.6 million.

The figures are part of a complex web of financial debts and assets involving the 31-year-old, revealed during Thursday's proceedings in the Federal Court.

The court heard Mr Mehajer claimed ownership of two properties, and a partial ownership in another seven, and held full and sole shareholdings in a number of companies.

During his testimony Mr Mehajer said he had been speaking with "overseas lenders" that were willing to provide him with the loans for the five proposed property developments that were all "in their early days".

The biggest of the five developments is on John Street in Lidcombe, the site of many of the controversial figure's previous apartment developments.

He revealed he wanted to borrow as much as $75 million for that development.

Mr Mehajer's testimony was one element in a day of complex evidence to determine the validity of his bankruptcy, which was declared by a federal court judge in March, and whether it could be overturned and the property developer could continue with his business interests.

'Complex' business interests

Mr Mehajer's lawyer David Hume argued there were "complexities" in his client's financial affairs, with his multitude of properties, numerous shareholdings, debts, assets and interest owing.

Mr Hume said it required a forensic accountant to sift through the detail to determine his client's solvency.

There were also issues surrounding the amount owed to the liquidator and petitioning creditor of Mehajer’s company SM Project Developments, with the amount owed ranging from $200,000 to $230,000 to up to $668,000.

He also highlighted the 10 concurrent criminal and civil cases involving his client, including family court proceedings.

However, Justice Michael Lee rejected the appeal, describing the evidence as "unsatisfactory".

"I have not in the least bit following the travails of your client," Justice Lee said.

Justice Lee said there would be a final hearing on Mr Mehajer's bankruptcy on June 21 and 22.