A handwriting expert testifying in a lawsuit filed by a Connecticut casino against Eugene Melnyk said it's "highly probable" the Ottawa Senators owner signed all the bank drafts at the centre of the dispute.

The lawsuit, filed on July 9 by the Mohegan Sun casino in Uncasville, Conn., alleges Melnyk tried to pay a debt with five bank drafts totalling $900,000 over the weekend of March 17, 2017, but those drafts were later "dishonoured" by a bank.

According to a statement of defence filed by Melnyk's lawyers in early October, the casino refused to cash his chips when asked and "induced" him to continue gambling, which led to the loss.

His legal team then asked the casino to change its complaint from a single loss of $900,000 to five, representing four $200,000 bank drafts and one $100,000 draft.

Since mid-October, Melnyk's lawyers have denied their client signed three of those drafts, worth $600,000, among other charges they said they can't answer because they're too vague or confusing.

On Nov. 15, the casino's lawyers accuse the other side of trying to delay the proceedings, calling some answers a "silly response" and arguing that under tribal law, none of Melnyk's defences stand up to scrutiny, except for the possibility Melnyk didn't sign the drafts.

The casino is run by the Mohegan Tribe of Connecticut.

The Mohegan Sun casino in Uncasville, Conn., in June 2012. (Jessica Hill/Associated Press)

Last week, the casino introduced a report by a handwriting expert who compared the two drafts Melnyk admits to signing with the three he said he didn't, along with two of his recent passport.

The expert said they're likely all from the same person.

"It is highly probable that the Questioned 'Eugene Melnyk' signatures appearing on D-3, D-4 and D-5 and the

[reported] Known signatures and passport signatures of Eugene Melnyk submitted for examination share common authorship," wrote James Streeter.

The next scheduled hearing is Dec. 17.