Embattled coalminer Nathan Tinkler and his wife could be made bankrupt over $440,000 in allegedly unpaid bills to a corporate adviser.
In the latest in a series of lawsuits targeting Mr Tinkler, corporate adviser BKK Partners has for the first time directly sued Rebecca Tinkler, who is trustee of the family trust.
BKK has filed two suits in an attempt to recover the money - one against Tinkler Group in the Federal Court, and the other against Mr and Mrs Tinkler in the NSW Supreme Court.
In a separate action in March, Mr Tinkler told the NSW Supreme Court that the family trust held assets of about $1.4 billion, but had debts of up to $600 million, and that Mrs Tinkler controlled the trust.
BKK was hired by Mr Tinkler in March last year to advise him on what turned out to be a failed bid to take over Whitehaven Coal for $5 billion.
According to a statement of claim filed with the NSW Supreme Court, the advisory group was to be paid a retainer of $50,000 a month.
While Mr Tinkler paid some of the invoices received, he allegedly failed to pay a November invoice for $220,000 and a February invoice for the same amount.
"The retainer agreement was entered into by Nathan Tinkler on behalf of the Tinkler Group, as well as its affiliates and related parties, which includes Nathan Tinkler personally and his wife, Rebecca Tinkler, who we understand is the trustee of the Tinkler Family Trust," Marc Ryckmans, a partner at legal firm Somerset Ryckmans, told BusinessDay.
"If we are successful in obtaining a judgment against them, then BKK would be entitled to commence bankruptcy proceedings against Nathan Tinkler and his wife."
Mr Tinkler's lawyer at DLA Piper declined to comment when contacted by Fairfax Media.
BKK's other case against the Tinkler interests is a winding-up application filed in the Federal Court in NSW against the Tinkler Group over unpaid fees of $220,000, an amount also claimed in the Supreme Court proceeding.
In April Mr Tinkler rid himself of two of his other court cases after paying a tax bill and settling a royalties dispute with former business partner Matthew Higgins.
Last week in the NSW Supreme Court, Ferrier Hodgson, the liquidator of another of Mr Tinkler's companies, Mulsanne Resources, alleged that Mr Tinkler, fellow director Matthew Keen and in-house lawyer Aimee Hyde traded while insolvent and breached their duties to the company.