The union representing rail workers in Canada has given a 72-hour strike notice to CN Rail, which means conductors across the country could be off the job starting Tuesday.

On Friday, Teamsters Rail Conference, which represents around 3,000 conductors,yardmen and trainmen with CN Rail, said union members handed the bargaining committee a 98 per cent strike mandate.

The next day the union issued an update, saying the company gave notice it was changing the terms and conditions of their collective agreement.

72 HOURS NOTICE <a href="https://t.co/cTYvBTn418">https://t.co/cTYvBTn418</a> <a href="https://t.co/44MDJoHTse">pic.twitter.com/44MDJoHTse</a> —@TeamstersRail

The union says the changes would include a two per cent wage increase and give the company the power to implement material changes, such as terminal closures, mandatory relocations and home terminal abolishment, with "little to no ability for the union to negotiate any protections for the members."

"Given the blatant provocation by the company, and potential irreparable harm that may be caused by the company's changes, the union is left with no choice but to serve the company with 72 hours notice," the notice to the company reads.

Job action is set to begin May 30 at 4 a.m. Members have been without a contract since July 2016.