OTTAWA -- Hundreds of usually buttoned-down federal civil servants gave Justin Trudeau and other members of his cabinet a rock-star reception Friday at the Lester B. Pearson building in downtown Ottawa.

The bizarre spectacle came as the Liberals held a cabinet orientation session at the fortress-like foreign affairs building on Sussex Drive.

Confused reporters arriving for a media scrum with Global Affairs Minister Stephane Dion were greeted by a massive, buzzing throng of federal employees inside the secure zone of the building's foyer.

The buzz from the female-dominated crowd soon made it clear they were on hand for a sighting of the prime minister, although any recognizable cabinet member would do.

When Harjit Singh Sajjan, the new defence minister, quickly strode through the lobby as one of the first to leave the orientation session upstairs, wild hoots and applause followed him out the door.

Dion was applauded when he arrived to speak to the media, and his answers to questions from journalists were uniformly cheered as well.

When one reporter asked about five female cabinet members who are listed as lower-level parliamentary secretaries in orders-in-council documents, the watching civil servants loudly groaned in dismay -- an echo of the kind of partisan excesses towards the media witnessed during the recent election campaign.

Trudeau finally arrived following Dion's press scrum, causing pandemonium.

In a routine that's become familiar in the three weeks since his Liberals won a surprise majority mandate on Oct. 19, Trudeau waded into the crowds wearing a huge grin and clutching hands.

After running the gauntlet of hundreds of cheering employees, the prime minister made a short impromptu address in both official languages.

"I'm truly touched by the enthusiasm, by the support, because we're going to have an awful lot of really hard work to do in the coming months, in the coming years, and we're going to need every single one of you to give us -- as you always do -- your absolute best," said Trudeau to more applause.

Conservatives have long complained of Liberal sympathies in the federal civil service but the Harper government's penchant for picking fights -- on everything from scientific advice to collective bargaining -- appears to have pushed the normally reserved bureaucracy past the point of caring about partisan optics.

This week, Trudeau sent a letter to all heads of missions freeing up Canada's diplomats to re-engage in public diplomacy after years of having to report every public engagement to Ottawa.

Some departments have also begun advising federal scientists that restrictions on discussing their work with the media and at conferences are being lifted, according to the Professional Institute of the Public Service of Canada.

The government confirmed that late Friday with a statement from Navdeep Bains, the minister of Innovation, Science and Economic Development. Scientists will be treated with respect, Bains said in a brief statement.

"That is why government scientists and experts will be able to speak freely about their work to the media and the public," he said.

"We are working to make government science fully available to the public and will ensure that scientific analyses are considered in decision making."