The union representing more than 9,000 Canada Border Services Agency employees says workers are set to strike on Friday if a deal is not reached with the federal government by then.
The Public Service Alliance of Canada says it has moved its strike deadline to Friday at 12:01 a.m. after extending negotiations with the Treasury Board last week.
Border workers were set to strike as early as 4 p.m. last Friday, but shortly after that deadline, a spokesperson for the union said negotiations would continue.
"We are still hopeful we can avoid a strike and potential disruptions at Canada's borders," said Sharon DeSousa, PSAC's national president, in a statement.
"No worker wants a strike, but we've set a firm deadline for this government to come to the table with a fair agreement."
The union has warned that similar job action three years ago nearly brought commercial border traffic to a standstill and caused major delays across the country.
The government says 90 per cent of front-line border officers are designated as essential, which means they can't stop working during a strike.
But union members can work-to-rule, and experts say that could cause serious slowdowns.