Opposition parties have opened a second political front in their battle to get information out of the Liberal government on an ongoing court case involving the military's former second-in-command.

Both the Conservatives and New Democrats have written to the House of Commons ethics and access to information committee to call for an emergency meeting on the case of Vice-Admiral Mark Norman, and for testimony from the country's top federal bureaucrat.

They're hunting for information related to the government's handling of the $668 million contract to lease a supply ship for the navy, which is at the centre of the criminal case against Norman.

The letter — a copy of which was obtained by CBC News — said MPs need assurances from Clerk of the Privy Council Michael Wernick that "all briefing notes, reports and emails related to the 16 communications between the President of the Treasury Board and the Irving Group of Companies since February 17, 2016" are secured and "have not been destroyed."

Treasury Board President Scott Brison has been accused by Norman's lawyers and opposition members of trying to scuttle the lease contract on behalf of a rival shipyard, Irving Shipbuilding of Halifax.

Lawyer Marie Henein filed a motion asking the court to force the Liberal government to turn over a host of confidential and secret cabinet documents related to the project — something the government has so far refused to do.

The letter also demands that Wernick account for "all briefing notes, reports and emails produced within the Treasury Board Secretariat related to Project RESOLVE since October 19, 2015" and ensure they also "have not been destroyed."

The Conservatives raised the possibility of the documents being destroyed last week in the House of Commons — an assertion Public Safety Minister Ralph Goodale dismissed as "absolutely absurd."

"If the honourable gentleman has an allegation of wrongdoing or of criminal behaviour, he should provide that information to the RCMP. He should also have the courage to make the allegation outside this House," Goodale said in response to a question from defence critic James Bezan.

In 2015, the newly elected Liberal government hit pause on the project — but news of the cabinet committee decision soon leaked.

The government later allowed the lease deal to proceed, but the ensuing political ruckus led to an RCMP investigation, which eventually led to a single breach of trust charge against Norman.

The Crown accuses Norman of being the source of the leak — something he denies.

The Conservatives and the NDP have seized on the Liberal government's refusal to disclose documents and have repeatedly hammered away on the issue during question period in the Commons, saying they want to ensure Norman gets a fair trial.

The response from the Liberal front benches has been that they cannot discuss the case because it is before the courts. That's likely to frustrate opposition attempts to question Wernick.

The Conservatives also have sent a separate letter, unsupported by the NDP, to the House of Commons justice committee.

They are asking Justice Minister Jody Wilson-Raybould to appear before the committee to talk about the government's policy on the invocation of cabinet confidences, as well as the government's use of Section 39 of the Canada Evidence Act to keep certain documents secret during a court proceeding.

Separately, NDP MP Charlie Angus has written to the CBC's ombudsman asking for policy reforms as it relates to the protection of confidential journalistic sources.

His concern stems from the fact that the reporter who first reported the leak, James Cudmore, left the CBC a few months after the story appeared and went to work as a policy adviser for Defence Minister Harjit Sajjan.

Angus claims the confidentiality guarantees "evaporate" when a journalist is hired by a government department they have investigated.

"I recognize Mr. Cudmore has every right to take a job opportunity presented to him," Angus wrote on Oct. 26. "At the same time, whistleblowers and anonymous sources have been critical to breaking some of the most significant stories of government wrongdoing in history, and the ease with which Mr. Cudmore was hired into the minister's office, potentially compromising his source, could be a chilling example for others interested in blowing the whistle."

Jennifer McGuire, editor in chief of CBC News, responded to Angus's letter on Tuesday. She said the guarantee of confidentiality is something granted by CBC News under its Journalistic Standards and Practices, and not by individual journalists. And the obligation does not expire.

"The departure of a journalist from the CBC does not change this," McGuire said in a letter addressed to the MP. "Both the former journalist and CBC News have continued obligations to respect the commitment given to the source."

"We take this pact very seriously and we defend it very vigorously. Former employees have under law an ongoing duty of loyalty to a former employer. In this case, all former CBC journalists who have committed to protect the identity of a confidential source, or have obtained any other confidential information in the course of their employment, have a continued obligation for maintaining that confidentiality."

McGuire pointed out that journalists, even former journalists, view the protection of sources as "sacrosanct" and that she does not believe that line was crossed in the Norman case.

"We have no indication that there is a breach of our processes in this case," she wrote. "I can assure you that CBC News will take all measures necessary to honour its undertaking and maintain the confidentiality of the source in our story."