HALIFAX -- Some military veterans who say they are so disabled by PTSD that they haven't worked since being released from the Forces will take their fight for long-term benefits to court Wednesday to argue they were wrongly shut out of support payments from Ottawa.

Stephane Hebert, who served in the military for 21 years before being medically released in 2007, is one of about a dozen veterans who have come forward so far as part of the proposed class action suit against the federal government.

Hebert, who served in Yugoslavia in 1992 and was later diagnosed with severe PTSD, said he didn't apply for disability payments because he was told wrongly that he would not be entitled to them.

He claims that when he eventually learned otherwise, federal officials told him he had missed a 120-day deadline.

"I was told I was not entitled to that, so in bouts of anger I just said, 'Yeah, I'll just leave it at that,"' the 48-year-old father said in an interview as he travelled from his home in New Brunswick to Halifax for the certification hearing in Federal Court.

"I had no choice today but to push for this class action for members who have been misled."

Dan Wallace, the lawyer handling the case, said the Forces's insurer led his client and others to believe they would not receive any payments based on calculations that used a formula that takes salary and pensions into account.

But Wallace argues that a previous court ruling in another matter involving veterans' benefits found the formula was flawed and should be overturned, meaning the class should apply for and receive payments.

A spokesperson for the Department of National Defence said in an emailed statement that the federal government will oppose certification of the lawsuit.

"The Crown will submit that the common issues as presented cannot be determined on a basis which is in fact common to all members of the class," wrote communications advisor Laura McIntyre-Grills. "In other words, the facts of this case does not meet the test for certification of a class."

Fernand Kenney, a veteran who is named in the proposed suit, launched the case last year after he was similarly rejected for disability payments related to post-traumatic stress disorder and his service in Bosnia in 1993.

Kenney claims in a four-page application filed in Federal Court that he was given the wrong information by the insurance provider and, as a result, did not go through a lengthy and costly process of applying for the benefits.

When he did, Kenney was also told he had missed the deadline for applications, even though he was initially told he wouldn't receive any money and shouldn't bother applying.

Wallace said it doesn't make sense that a veteran pays premiums for his full military career and isn't able to collect on them because incorrect information was used from an insurance provider.

"If you know you're going to get zero dollars a month, of course you're not going to go through all the hoops and expenses of filling out all the forms," he said.

"They served for an extended period of time and paid into an insurance benefit and when they needed that benefit, it wasn't there for them."

A Department of Defence spokeswoman was not able to comment on the matter.

Wallace says Kenney, now 57 and living in Quebec, is severely disabled and has not worked since he was involuntarily released from the Forces in 2005. Hebert also says he hasn't worked since his release due to PTSD and physical injuries related to his service.

Wallace didn't know the dollar value of the case, but estimates Kenney and Hebert would stand to receive about $50,000 each.

This latest battle comes after Ottawa settled with about 7,500 claimants in a $887.8-million class-action lawsuit in 2013 over their clawed back pension benefits.

Dennis Manuge launched the suit for veterans whose long-term disability benefits were reduced by the amount of the monthly Veterans Affairs disability pensions they received. The Federal Court said it was unfair of the federal government to treat pain and suffering awards as income.