The largest federal public service union in the country said that if an agreement with the federal government is not reached by 9 p.m. Eastern Time on Tuesday, it will launch a strike the next day.

The Canadian Public Service Alliance said that about 155,000 employees are ready to walk off the job starting Wednesday, including 35,000 workers from the Canada Revenue Agency.

Contract negotiations mediated between the union and the Treasury Board continued over the weekend in what the union described as the government's last chance to reach an agreement.

For his part, Chris Aylward, the union's national president, said at a Monday morning press conference that some progress had been made—but not enough to call off a strike.

Aylward added: "Despite some progress at the bargaining table, our members are frustrated that while negotiations are delayed, they continue to fall behind. We have already been at the table for nearly two years and these workers cannot wait any longer. That is why we are setting the clock in this round of bargaining."

He also said CRA workers returned to the bargaining table on Monday and Tuesday after announcing their separate strike mandate on April 7.

He continued that unless they reach their own agreement by Tuesday evening, these workers will also strike.

The biggest sticking point in the talks appears to be wages, with the union calling for increases to keep up with inflation and rising living costs.

The Treasury Board also issued a statement Monday afternoon saying it offered the union a 9 percent increase over three years on Sunday, based on a recommendation from the third-party Public Interest Commission.

Last year, the government offered an annual wage increase of about 2 percent over four years, representing increases of 1.5 percent for 2021, 3 percent for 2022, 2 percent for 2023, and 1.75 percent for 2024.

The union has pushed for annual increases of 4.5 percent for the next three years.

Also, Prime Minister Justin Trudeau told reporters Monday morning that although inflation has dropped, the government needs to do its part to support workers who are currently struggling.

He said he hopes to reach an agreement, adding: "There has been progress and constructive offers and we really hope we can resolve this."

In addition to wage increases, the union also wants to negotiate greater limits on contract work, more anti-racism training, and remote work conditions.

In this regard, the Treasury Board said in its statement that the union made it clear that enshrining remote work in the collective agreement is a "deal breaker."

The board said that including the clauses as drafted by the union "would severely affect the government's ability to deliver services to Canadians and limit its ability to effectively manage employees within the public service."

In the event of a union strike on Wednesday, many federal services could be affected from tax processing to passport renewal—as departments and agencies point to essential services that will continue during the strike and which may be disrupted.