MELBOURNE (Reuters) - Liquidators of one of Australian coal magnate Nathan Tinkler's companies have launched a lawsuit against the struggling tycoon and fellow directors for insolvent trading, one of his creditors, Blackwood Corp Ltd (>> Blackwood Corp Ltd), said on Thursday.

If the court finds Tinkler's privately owned Mulsanne Resources was conducting business while not having funds to meet all its obligations, Tinkler could face penalties that might force him to sell down his 19 percent stake in Whitehaven Coal Ltd (>> WHITEHAVEN COAL LIMITED), now worth A$357 million ($367 million).

"The directors of Mulsanne strongly deny allegations of trading while insolvent and will strongly defend any legal action instigated by the liquidators," Tinkler's spokesman said in a statement emailed to Reuters.

Liquidators were brought in after Mulsanne failed to follow through on an agreement to buy a one-third stake in Blackwood Corp Ltd (>> Blackwood Corp Ltd) for A$28.4 million last year.

"If the court finds the directors and officers liable for insolvent trading, it may make compensation orders against them personally for which they will be jointly and severally liable," Blackwood said in a statement emailed to Reuters.

At hearings in March, Tinkler said he thought he was going to have funds to pay for the Blackwood shares from a deal he had proposed to Hong Kong-based trading firm Noble Group Ltd The deal with Noble did not go ahead and he admitted there had never been any written agreement with Noble.

"I got left holding the can," he told the court.

Whitehaven shares sank to a four-year low of A$1.775 on Thursday and closed down 3.7 percent at $1.83. Blackwood shares have not traded since April 24.

($1 = 0.9720 Australian dollars)

(Reporting by Sonali Paul; Editing by Matt Driskill)

Stocks treated in this article : Blackwood Corp Ltd, WHITEHAVEN COAL LIMITED