Mr Baron told his former co-workers that he had won a stake in the $50 million jackpot with a separate ticket to the one he purchased on behalf of the syndicate.

Standing outside his Geelong property in a dressing-gown on Sunday afternoon, Mr Baron insisted he had evidence to substantiate his claim, which had been handed over to his lawyer.

The 49-year-old had repeatedly denied winning the massive windfall to several members of a 16-person syndicate, who had entered the lottery on a regular basis since 2009. He is understood to have told another former colleague that he had received a significant inheritance.

An ASIC search has revealed Mr Baron established an investment company within days of winning. Within months, he had purchased a new home in the Geelong suburb of Lara, paid $200,000 for a convertible BMW M4 and bought property for his son.

Fairfax Media revealed exclusively that the angry syndicate members are about to take Supreme Court action against Mr Baron, who collected $20 each week from his co-workers and entered the draw via an online Tatts Group account. A writ is expected to be lodged this week.

The syndicate members live in Geelong and the Bellarine Peninsula and met while working as couriers for logistics company Toll Group.

The day after three winning entries shared a first-division pool of $50 million on October 16, Mr Baron called in sick and took the day off work. The following Monday, he suddenly resigned and told several co-workers he was suffering from a medical condition.

In an extraordinary twist, a syndicate member and Toll Group courier was hired by Tatts Group to deliver champagne to Mr Baron shortly after the lottery win.

Mr Baron suddenly distanced himself from most of his colleagues in the syndicate, aside from one woman with whom he is now romantically involved. The woman has also resigned from Toll Group and is not party to the legal proceedings about to be initiated by the 14 other syndicate members.

The disgruntled syndicate members will allege in court documents that they were one of three winning groups to collect $16,666,666.67 in the $50 million jackpot, and each member is entitled to more than $1 million. They will claim their former friend and colleague reneged on a deal to share the winnings.

The day after the Powerball draw last October, Tatts Group released a statement from the three winners, including one anonymous response believed to be from Mr Baron.

"I'm still in disbelief ... I don't need that amount of money, it's too much for me!" he told a Tatts official.

"I'm going to share the prize money with my family. I'll make sure it doesn't change who I am, but I'll definitely be able to live a better lifestyle, with a few more toys," the anonymous winner said.