The finances of the embattled Obeid family have been given a $10 million boost with a property sale that could help pay for their numerous legal battles.

As family patriarch Eddie Obeid swapped his stately Hunters Hill mansion for a jail cell, questions have been raised over the sale to a company whose director is a 25-year-old Chinese woman living in a modest apartment in Mascot.

The clan have legal bills believed to be in excess of $5 million following Obeid's trial for misconduct in public office, for which he was jailed on Thursday for at least three years, and their failed battle against the Independent Commission Against Corruption and staff.

They also have ongoing cases against the Australian Competition and Consumer Commission and the Australia Taxation Office.

Like many other deals involving the Obeid family, the building on the corner of Wattle and Broadway in Ultimo has been mired in controversy.

In 2002, South Sydney Council sold the building to the Obeids at what was considered a bargain price of $1.8 million.

There was no advertising, no tendering process and the price paid was less than the valuation.

At the time the council's general manager, Michael Whittaker, claimed that the Obeids were the "only real potential buyer". Eyebrows had already been raised at the peppercorn rent the Obeids had been paying the council for the building, which housed two restaurants including the Little Snail.

Eddie Obeid, who was an MP at the time, had personally intervened to help secure the bargain lease deal when, in June 1997, he gave a personal guarantee that renovations on the buildings would be completed by his son Paul's company, Windaru Pty Ltd.

The promised renovation by the Obeids allowed them to secure a 20-year lease. Paul Obeid proceeded to rent out the buildings for 20 times the amount they were paying to council. It is not known whether any renovations had been done when they bought the building a few years down the track.

Now Fairfax Media can reveal that in September, the Obeids sold the building for $9.76 million to R&C Real Estate Investments Group, which was formed only a fortnight before the sale.

The sole director is Yizhi Rui, 25, but the shareholder appears to be a relative in Nanjing, China.

At the time of the sale Paul and Damian Obeid had signed a $241,406 per year rental with the vice-chancellor of Notre Dame University, Professor Celia Hammond.

A restaurant in the building was paying rent of $132,000 per year.

At the same time the Obeids were selling their Broadway building, they also took out a $4 million mortgage at 20 per cent interest per annum on their Walcha property.

The family has also remortgaged the family home Passy, leaving only 30 per cent equity in the house that is valued about $8 million.

In November a caveat was lodged on the house to protect a loan to Eddie Obeid's wife Judy from Garry Maroon of Telopea.

On the upside, they still have their controversial rural spread Cherrydale Park at Bylong, which will feature during Eddie and his son Moses' criminal trial, set for 2017, over coal leases that were granted over their land.

The family also has the multimillion-dollar penthouse on top of the Rydges Hotel in Port Macquarie, which a corruption hearing heard was funded with part of the $30 million acquired from the corrupt coal mining deal.

And in winter, the family's ski lodge at Perisher is still available.

The family's other real estate investments include a prospective development in Restwell Street, Bankstown, which Paul Obeid is pursuing with Labor party aspirant Remy Wehbe.

The Obeid family is also marketing residential blocks in a luxury development called Catarina Village, at Lake Cathie, south of Port Macquarie.

The Obeids obtained the 16-hectare block of land on Ocean Drive in 1988 from the late corrupt former Strathfield mayor John Abi-Saab.

Another son, Gerard Obeid, bought a $1.2 million house in Port Macquarie after the ATO snipped $1.3 million from the $2.7 million sale of his Hunters Hill home in 2014.

In 2015 he told News Corp that with his BMW and Lexus parked outside his new Port Macquarie spread, he could understand why locals suspected him of building skywards.

"Because we're Obeids – that's what we do," he said. "We develop."