Canada's biggest federal public service union is preparing to ramp up its ongoing strike by moving picket lines to strategic locations such as ports on Monday, as both sides continued to accuse each other of poor communication.

In a Sunday interview with The Canadian Press, Public Service Alliance of Canada National President Chris Aylward said civil servants need to further affect the economy to push Ottawa for a solution.

"We're trying to have picket lines across the country in some strategic locations where it's going to impact the government, and we're actually going to be escalating those actions … whether that's ports across the country, or anything like that," he said.

"It has a very wide-ranging impact on Canadians and the Canadian economy as well. Because imports (and) exports are being delayed and disrupted," he said, while insisting he doesn't want to unsettle Canadians' lives.

"We're trying to get through this as quickly as we possibly can."

Picket lines have so far largely been confined to government buildings, constituency offices and landmarks such as Parliament Hill.

Aylward said Ottawa presented a revised contract proposal on Saturday following a public tit-for-tat over a breakdown in communications, adding the union responded that same day.

As of 2 p.m. Sunday, the union said it had not heard back from the federal Treasury Board. Yet the office of Treasury Board President Mona Fortier, the Liberal minister overseeing the negotiations, said it had submitted a second offer Saturday at 8:30 p.m. and was waiting for a reply.

"The Government recognizes and respects the PSAC members’ right to strike," spokeswoman Monica Granados wrote in an email.

"We are making every effort to ensure that strike action is as short as possible to restore services to Canadians while ensuring a fair and reasonable deal for employees and for Canadians."

Aylward later confirmed the government had sent a response on Saturday evening, but said the revised proposal did nothing to advance negotiations on salaries — one of the primary issues at play.

"There has been very little progress at the table since yesterday," he said Sunday as one of Canada's largest strikes entered a fifth day.

"This government doesn't seem to be acting in any sense of urgency at all, which I guess demonstrates a lack of willingness on the government's part to get this done."

More than 100,000 union members walked off the job Wednesday after contract talks broke down following months of negotiations.

Aylward said the union's top three priorities are wages, remote work and job security in relation to layoffs.

"We've got agreement on some of the other issues, such as the mandatory training for anti-racism and anti-discrimination in the workplace. But for the three main issues, there is no agreement done yet," he said.

The union is pushing for annual raises of 4.5 per cent over each of three years, dating back to 2021. The Treasury Board said it has offered the union a nine per cent raise over three years on the recommendation of the third-party Public Interest Commission.

Labour economists have said PSAC's sheer size means the negotiations could influence future collective bargaining talks for public workers employed by provinces, as well as the private sector. They particularly hone in on adjusting wages for a period of historic inflation, and enshrining a right to work remotely, even if curtailed to certain weekdays.

"When the federal government represses wages on its own employees, all they're doing is repressing wages for all workers across the country," Aylward said.

He argued the scale means Prime Minister Justin Trudeau needs to get involved.

"He's the only one that can really, at this point, unlock some of those key issues," he said.

"I've been involved in this union a long time and I don't think any prime minister has actually leaned in on negotiations, but we're in uncharted waters."

Both sides accuse each other of cherry-picking facts they present to the public to make the other seem unreasonable.

Ottawa claimed the union agreed to a meeting Saturday but cancelled nine minutes later, holding a press conference instead.

Aylward said the government sat silent for 30 hours and only offered the meeting once it got wind of a press conference, but Ottawa claimed an inverse series of events, with them tabling an offer and PSAC then calling a press conference.

The two sides also insist they could not reach each other last Friday.

"For the employer to say we weren't available, I will unequivocally say that that is not true," Aylward said Sunday.

Aylward confirmed the findings of a decision last Thursday by the federal labour board over "significant concern" about the recent strike vote because of a low turnout and irregularities.

The board found the union failed to properly alert members that it had shortened the voting period by eight days, moving the deadline from April 19 to April 11.

Only about 35 per cent of members of the bargaining unit, or 38,207 people, cast a ballot — and 80 per cent of them were in favour of a strike mandate.

Aylward said those numbers are correct, but the union felt the need to call a strike after a lack of progress in bargaining. He noted the labour board upheld the vote, ruling a different result was unlikely even if the original deadlines had been observed.

A lot of those members obviously didn't go vote either way — didn't vote yes, didn't vote no — but when the strike was called, they showed up," he said.

"They voted with their feet."

Aylward also repeated a claim that the union has access to cash beyond its fund for paying a daily $75 to those on the picket line, which could amount to roughly $7.5 million per day. The union's most recent available financial statements suggest it had about $43 million in its strike fund at the end of 2021.

"The strike is not going to be over because we can't pay strike pay; I can guarantee you that," he said. He didn't say whether additional resources include loans or transfers from other labour groups.

"We have access to funds, (so) that I am not concerned one bit about running out."

This report by The Canadian Press was first published April 23, 2023.