NDP Leader Jagmeet Singh is asking the prime minister to allow more members of his party to be briefed on foreign interference attempts, after the leaders of the Conservatives and Bloc Québécois declined to obtain the required security clearance.

In a letter addressed to Prime Minister Justin Trudeau on Thursday, Singh said he wants those two spots given to members of his team who would accompany him in the briefings.

Singh also asked Trudeau for a briefing on how much he can and cannot say after reviewing the intelligence.

"I expect that I would be able to speak ... freely about my conclusions based on the intelligence I am allowed to view and that my ability to be critical of the government’s actions will not be constrained," Singh said in his letter to Trudeau.

"I will be seeking assurances on this point in writing."

A spokesperson for the Prime Minister's Office said they are reviewing the letter.

Tory Leader Pierre Poilievre and Bloc Leader Yves-François Blanchet both suggested in rejecting Trudeau's offer that it seemed like a way to trap them into agreeing not to speak about the allegations in public.

Special rapporteur David Johnston said in his first report on foreign interference Tuesday that opposition leaders should take the opportunity to see how he reached his conclusions about alleged interference attempts in the 2019 and 2021 federal elections.

Johnston said the confidential information would be provided to those who got the right security clearance.

Opposition party leaders expressed their displeasure with Johnston's report because he advised against a public inquiry into foreign interference, though he promised to hold some public hearings of his own.

The former governor general said making more information public would run the risk of breaching the trust of Canada's security allies and endangering intelligence sources.

The Conservatives have argued that Singh can force the Liberal government to hold a public inquiry, since the NDP is propping up the Liberal government with a confidence-and-supply agreement.

Under the deal, the New Democrats agreed to support the minority Liberals on confidence votes until 2025 in exchange for movement on shared priorities.

Singh said pulling out of that agreement is not something he wants to do now, but he said he will continue to explore other ways to apply pressure to the Liberal government.

In his letter, Singh said a public inquiry would restore trust in Canada's institutions, after a series of media reports brought allegations that China meddled in the last two federal elections to public attention.

Johnston's first report said the media reports, which cited unnamed national security sources and classified documents, lacked context.

He said he did not find evidence that the Liberal government knowingly ignored interference attempts or recommendations from national security agencies. But he did find serious gaps in how intelligence is shared within the government.

"I believe that confidence in our democratic institutions has been damaged by your decision to not call a public inquiry into foreign interference," Singh's letter said.

"There is still time to repair this damage and, once again, I urge you to reverse course and call the rigorous, public and independent inquiry that Canadians deserve."

This report by The Canadian Press was first published May 25, 2023.