A new lawsuit filed against the National Hockey League by two former players alleges that three in 10 retired players have, or will have, brain damage from head injuries or concussions.

The startling allegation is being made in a statement of claim filed by Sasha Pokulok, who was selected by the Washington Capitals with the 14th overall pick in the 2005 NHL draft and Simon Danis-Pepin, a 2006 second-round pick of the Chicago Blackhawks.

In the lawsuit, lawyers for the players say the National Football League filed an actuarial study on Sept. 12 that demonstrated that 3 of 10 retired NFL players have or will have brain damage from head injuries or concussions.

"Since studies have shown that hockey players and football players receive concussions at a similar rate, it is likely that former NHL players have, or will have, brain damage at similar rates as retired NFL players," the lawsuit says.

The lawsuit did not specify the studies in question.

NHL deputy commissioner Bill Daly declined to comment. Pokulok and Danis-Pepin's claims have not been proven in court.

For years, the NFL denied that its players had a high rate of severe brain damage. But earlier this week, the league admitted in court papers that nearly one-third of its retired players develop long-term brain problems and that those problems surface at appreciably younger ages than the general population.

In the NFL's case, both the league and lawyers for the former players expect that only a few dozen former players would receive payments of as much as $5 million if they are diagnosed with Parkinson's disease, amyotrophic lateral sclerosis or chronic traumatic encephalopathy (CTE), a degenerative brain disease which at this point can be identified only during an autopsy.

But some 28 per cent of players, or 5,900 former players, would develop injuries for which they would merit compensation.

"Former NHL players are uniting to send one resounding message," Pokulok and Danis-Pepin's lawsuit says. "They signed up to play hockey knowing that they might get injured and dinged, but they did not sign up for brain damage."

The lawsuit says Pokulok played under an NHL contract for three years and suffered multiple head traumas during his career, including in training camps, NHL rookie games, and prospect and main camps. It adds that he was never warned by the NHL of the negative health effects of head trauma.

The players are seeking more than $5 million, although the specific amount was not listed.

The claim is the latest of at least six filed against the NHL by former players over concussion-related health problems. The cases will be heard collectively in Minnesota.

Pokulok, a defenceman, played college hockey at Cornell before he was drafted and never played a game in the NHL, splitting time between 2006 and 2010 with the American and East Coast Hockey Leagues.

Danis-Pepin, also a defenceman, was drafted by Chicago out of the University of Maine. He, too, split time in the AHL and ECHL between 2009 and 2014. He never played a game in the NHL.