NDP Leader Tom Mulcair is demanding Prime Minister Stephen Harper fully defend Canada’s supply management system at the Trans Pacific Partnership negotiating table, accusing the Conservatives of creating a “climate of uncertainty” around the future of the country’s dairy, eggs and poultry sectors.

The demand comes four months before a scheduled federal election and with a summer of campaigning looming, with the agricultural community poised for a fight over supply management.

In a strongly worded letter dated June 26 and obtained by iPolitics, Mulcair calls on the prime minister to “commit to defending supply management in its entirety and reassure Canadians that it will be protected in all future negotiations.”

“Your evasive words earlier this week only heighten the uncertainty felt by Canadian producers and their families, whose livelihood depends on supply management,” Mulcair wrote, referring to comments made by the prime minister in Quebec City last week.

On Thursday, Prime Minister Stephen Harper told reporters in Quebec City it was “essential” that Canada be part of the pending TPP deal, but pledged a deal could be reached without undermining Canada’s supply managed system.

“I believe these negotiations are going to establish what will become the basis of the international trading network in the Asia Pacific. It is essential in my view that Canada be part of that – that the Canadian economy be part of that,” the prime minister said.

“At the same time, we are working to protect our system of supply management and our farmers in other sectors.”

Today, an unsolicited response from International Trade Minister Ed Fast’s office to this story did not address the issue of supply management directly, but included a political volley of its own.

“Canada has finalized an FTA with the EU and is negotiating with the TPP. If Mr. Mulcair wants to be Prime Minister he needs to tell Canadians where he stands on these agreements, and stop speaking out both sides of his mouth,” Max Moncaster, Fast’s press secretary, wrote.

Prompted on the supply management issue, Moncaster said the Conservative government is “committed to defending our system of supply management,” adding, “Reports of a deal are false. Reports that Canada has made particular concessions are false. Negotiations are ongoing.”

The prime minister, Fast’s office said “will only sign an agreement that’s in Canada’s best interests, ” noting the federal government “will continue to promote Canadian trade interests across all sectors of our economy, including supply management.”

U.S. trade officials, including Trade Representative Michael Froman, have publicly stated their dissatisfaction at Canada’s supply management system.

In his letter Friday, Mulcair said the lack of specifics, coupled with remarks like the ones recently made by retiring Edmonton Centre MP Laurie Hawn (who called the supply management system “an anachronism that needs to disappear”) have created “a climate of uncertainty that you [the prime minister] must respond to.”

“Dairy producers, among others, are even more concerned after seeing your government make significant last-minute concessions during negotiations to conclude the Canada-EU Economic and Trade Agreement,” Muclair added.

Under CETA, European cheese makers were granted an additional 17,000 tonnes of quota access into the Canadian market.

Canada’s dairy farmers say the new quota amounts will cost the Canadian dairy industry more than $300 million in losses, while the federal Conservatives have insisted the concessions do not undermine the supply management system. Farmers, Fast has said, will be compensated if the new tonnage negatively affects their industry.

A similar compensation is reportedly in the works for the Trans Pacific Partnership (TPP) agreement. In an interview with CTV’s Question Period over the weekend, Fast brushed those reports aside, calling them nothing more than speculation.

The heightened political interest in the future of Canada’s supply management system comes after the U.S. Congress agreed Wednesday to pass Trade Promotion Authority legislation. Commonly known as fast-track authority, the legislation submits any final vote on the pending multi-billion dollar TPP deal to a simple yes/no vote, without amendments.

The legislative development was seen as indispensable to negotiators from the 12 countries — including the U.S., Canada and ten Asian economies — since without it, Congress could have rolled back key provisions of the deal.

Canada is facing increased pressure from Australia, New Zealand and the United States to open up its supply managed sectors, which are angling for more access to Canada’s dairy and poultry markets.

Agriculture Minister Gerry Ritz has repeatedly said Canada will not be bullied into making agricultural concessions at the negotiating table, often pointing in past interviews to the U.S.’ former-inability to secure fast-track authority and its own heavily subsidized cotton, rice and sugar industries.

Now, with fast-track authority firmly secured, TPP negotiations are expected to heat up again, with reports a final deal could be reached by August.

With files from Canadian Press.