The team's players have hired Montreal-based lawyer Michael Cohen, who sent a cease and desist letter to the Habs owners and the NHL on Friday.
They're claiming it would be unlawful for the players to be locked out — something the league plans to do if a new collective bargaining agreement isn't reached by Sunday — because the NHLPA isn't certified by the Quebec Labour Board.
Under Quebec law, a union must have that certification for an employer to enact a lockout, according to the NHLPA.
Bill Daly, the NHL's deputy commissioner, referred to the matter as a "distraction" that was "not unexpected."
"It will be handled in due course, one way or the other," Daly wrote in an email on Sunday night.
According to a union source, the Canadiens players plan to submit an application to the Quebec Labour Board this week unless the league stops threatening a lockout. The board could keep the team from locking out its players.
Donald Fehr, the NHLPA's executive director, said repeatedly that his membership would be willing to continue negotiating while the league conducts business as usual. However, commissioner Gary Bettman has made it clear a lockout will be enacted if a new deal isn't reached by 11:59 p.m. ET on Saturday.
That seems unlikely after another weekend passed with no signs of progress. The sides last sat down together for a formal bargaining session on Aug. 31 — although Bettman and Daly met informally with Fehr and his brother Steve Fehr twice in New York on Friday.
The deal that expires this week is the one that was signed after the entire 2004-05 season was lost to a lockout. Members of the Habs believe the NHL doesn't have the legal authority to close the doors on them again.
"The NHL seems content to lock out the players if an agreement isn't reached this week, and we would like the Quebec Labour Board to step in and inform them that their lockout would be in direct violation of the Quebec labour laws," forward Erik Cole said in a statement.
Training camps are scheduled to open around the league on Sept. 21 and the regular season is due to begin Oct. 11.