Canada’s largest federal public-service union and Ottawa are bothwarning of likely service disruptions as nearly one-third of all federal workers remain on strike.

The job action taken by members of the Public Service Alliance of Canada could amount to a complete halt of the tax season, slowdowns at the border and pauses to new EI, immigration and passport applications.

In one of the largest strikes in Canada history, government workers walked off the job as of 12:01 a.m. ET Wednesday, hitting the picket lines at some 250-plus locations across the country.

The bargaining groups involve some 155,000 federal public servants, including 35,000 Canada Revenue Agency staffers and about 46,000 essential workers who are not part of the strike action.

The union is asking for a 13.5 percent raise over the next three years, saying the increases are necessary to keep pace with inflation and the cost of living.

The Treasury Board and the CRA both say they have offered the union a nine percent raise over three years, on the recommendation of the third-party Public Interest Commission.

PSAC’s national president Chris Aylward told reporters Wednesday that members are willing to strike for “as long as it takes.”

“Workers are fed up, workers are frustrated and workers are saying, ‘Enough is enough. We’re not going to take the garbage anymore.'”