Portions of Harold Leduc's letter were read out by the official Opposition Wednesday in the House of Commons.
NDP veterans critic Peter Stoffer says the two breaches of Leduc's privacy, in which his diagnosis of post-traumatic stress was passed around the review agency, amounted to a drive-by smear.
"Mr. Prime Minister, I implore you to show the harm from these privacy breaches," Stoffer said, reading from the letter. "Please stop the abuse, investigate the disrespect (and) fix the human damage before another veteran is harmed or takes his life."
Leduc, who spent over 20 years in the military and retired as a senior warrant officer, claims he was the victim of a smear because he often sided with ex-soldiers in his review of their cases.
Since his case accusations surfaced, other veterans have come forward to say they've been treated disrespectfully before the 24-member board, which is where ex-soldiers can appeal when they're unhappy with the benefits decisions of federal bureaucrats.
The chairman of the board, John Larlee, refused to answer questions about the case during an appearance before the Commons veterans committee on Tuesday, citing privacy issues.
Veterans Affairs Minister Steven Blaney stood by the agency and ducked the call for an investigation, claiming Stoffer has consistently voted against the military.
"Any breach of privacy is totally unacceptable," Blaney said.
The minister also noted that Veterans Affairs Canada has tightened up its handling of private information following an earlier scandal involving advocate Sean Bruyea. His medical information was stitched into a ministerial briefing note in 2006 in violation of the federal Privacy Act.
No one was fired over the incident, but several bureaucrats were reportedly disciplined.
A spokeswoman for Blaney says the minister is considering even more stringent privacy protection. But Codie Taylor did not say what those measures might include, or when they would be applied.
Leduc's privacy was breached twice and one of the incidents happened after the Harper government said it had imposed stricter rules.
He has appealed to the prime minister privately, and repeatedly, in the past to call a judicial review of the board, which has been riven by in-fighting — up to and including multiple human rights harassment complaints.
According to letters obtained by The Canadian Press, the Prime Minister's Office has in almost all cases referred Leduc's calls for an investigation back to Veterans Affairs.
But Blaney has refused to call a probe, saying the review board is an "arms-length agency" that manages its own affairs.
Both the New Democrats and the Liberals have said the board is not out of reach and at the very least should be either abolished overhauled.