Former minister Carl Scully said that after the government had completed an exhaustive tender process in 2000, Mr Obeid had sought an extension to one of the leases - but did not tell him of his family's involvement.

"I flatly refused this request," Mr Scully told Fairfax Media. "This was not well-received and ... Eddie became quite angry. It was only after I left politics that an allegation was made to me that Eddie had at the time in question a direct commercial interest. If the allegation is true, then it would explain the overreaction to my decision."

Another former minister, Eric Roozendaal, told Fairfax Media Mr Obeid had discussed the leases with him but did not disclose his interest.

Mr Obeid is also alleged to have misused his position as an MP between 2005 and 2008 to influence public servants to make decisions favourable to Direct Health Solutions (DHS), without disclosing that he and his family had an interest in that company. Fairfax Media has previously revealed that the former Labor powerbroker arranged private meetings with the former state treasurer Michael Costa to advance the business interests of DHS, which was secretly owned by his family.

DHS, which secured hundreds of thousands of dollars in government contracts, operates a sick-leave system designed to reduce absenteeism.