The NHL’s legal battle against former referee Dean Warren over $250,000 of unpaid severance could reach Canada’s highest court.

According to an April 8 letter from the league's lawyers obtained by CTV News and TSN, the NHL plans to ask the Supreme Court of Canada to take on its case.

Over the course of nine seasons, Warren was one of the NHL's top referees, officiating more than 500 games, including many in the playoffs.

But in 2008, the official was unexpectedly fired by the league for what it called substandard performance.

Warren believes he was really pulled from the ice because he was aggressive in his role as vice-president of the union representing NHL referees.

"I had a long history of supporting a lot of the guys and supporting a lot of the guys in their issues, and, quite frankly, the association didn't step up for the guys," said Warren.

A year after he was let go, Warren asked the Ontario Labour Relations Board to order the NHL to reinstate him.

The OLRB ruled against him and Ontario's Superior Court supported its decision.

However, while the OLRB said the NHL didn't have to provide Warren with a severance because too much time had elapse since his firing, Ontario's Superior Court disagreed.

At issue is a clause in the NHL's agreement with officials that says if a fired referee pursues legal action against it, that official has "waived (their) right to receive any of the benefits provided for" in the union's contract.

The league proceeded to appeal that result in Ontario's Court of Appeal in March, but it declined to hear its arguments. This set in motion the NHL's decision to appeal to a higher court.

Warren, 52, says he has spent several thousand dollars battling the league, but doesn't plan give up anytime soon.

“The same as the referee in a game would make a call that they thought was the right call, this is the right thing to do and I don’t think you can step away from that at any cost,” said Warren, who owns and runs a golf course near Hamilton, Ont.

“They think they are above the laws of the land and the laws here in Canada and that’s a problem.”

Andrew Langille, a Toronto-based labour lawyer who is not involved with the case, said employers aren't technically allowed to refuse severance payments.

"They are violating, in my opinion, the Employment Standards Act in trying to insert a term into the collective agreement that breaches the employee's right to obtain severance," said Langille.

The NHL did not respond to an emailed request for comment.

With a report TSN's Senior Correspondent Rick Westhead