The ATO has pursued Tinkler’s Hunter Sports Group over a $2.7 million debt as creditors continued to file claims and lawsuits multiplied against an unwinding empire of coal and sports assets.

Hunter Sports Group owns Newcastle’s Jets soccer team and Knights rugby team.

The ATO has also filed wind-up proceedings for his Tinkler Group Holdings Administration and Queen St Capital.

Market speculation has suggested creditors would take control of Tinkler's 19.4% stake in Whitehaven Coal - a holding earned when he merged his companies Aston Resources and Boardwalk Resources into the miner - in a move that would almost certainly end the coal entrepreneur's corporate endeavours.

Tinkler, who now lives in Singapore, holds a key $560 million shareholding in Whitehaven Coal.

The entrepreneur, who is believed to hold $500 million of personal debt, also failed to raise the finances in August to fund his $5.3 billion privatisation bid for Whitehaven Coal.

He subsequently criticised the board of Whitehaven for failing to control costs at its New South Wales operations, as the company’s share price plunged by 50% over the past six months.

Reuters reported that his private jet and helicopter, estimated to be worth $45 million, were seized last week by receivers who took control of Tinkler’s company THGA Aviation.

Tinkler has also been in a legal battle with former business partner Matthew Higgins over royalty payments from the NSW mine that first made their fortunes.

Higgins, who used to run Tinkler's maintenance business in Muswellbrook, is taking civil action in the Brisbane Supreme Court to gain access to the financial records of Oceltip, in which both are directors and shareholders.

The case includes allegations that Tinkler diverted funds from Oceltip's bank account without Higgins' knowledge or approval.