HALIFAX -- The Nova Scotia Teachers Union is resuming work-to-rule on Monday, saying it has lost confidence in Premier Stephen McNeil after he said two new "self-directed days" offered in a tentative agreement should be used for marking and classroom preparation.

NSTU president Liette Doucet said the union had understood the latest tentative agreement allowed teachers to decide how to use the non-teaching days, which the union had originally described as "two paid days off" in a memo to its 9,300 members.

"The premier is already backing away from commitments made in the new tentative agreement," she said in a news release Friday.

"If the premier is capable of misleading our members about two self-directed development days, then he is capable of misleading parents about the $20 million outlined in the deal to improve classroom conditions."

Doucet said documents received in the collective bargaining process indicated the teachers could use the days as they decided.

The premier said Friday he doesn't believe there should be any confusion over what teachers have interpreted as two days off in the new contract offer.

McNeil said the days are meant for preparation time and marking time for teachers.

"At no time during our conversation has that been part of the conversation. I think any reasonable Nova Scotian would tell you that when teachers were telling us that classroom conditions were what their focus was, that if they were going to have more time that it would be for prep in those classrooms or marking," he said.

McNeil was asked what he would say to parents about a potential return to work-to-rule.

"I have a responsibility not only to deal with the bargaining unit but to ensure that I can provide services to all Nova Scotians," he said in Wolfville, N.S., at a meeting of Atlantic Canadian premiers and several federal ministers.

He said his government has made investments in the classroom and is prepared to do more to improve the system.

"I need to have this contract behind us so we can continue to work to make sure we can make those investments."

Union members have twice rejected contract agreements recommended by the union executive and voted overwhelmingly in favour of a strike.

Teachers will vote on the latest agreement Feb. 8.

The teachers' last contract expired on July 31, 2015.

Teachers began a work-to-rule campaign on Dec. 5 that had a sweeping effect on school life across Nova Scotia, cancelling shows, trips and sports.

The union edict stipulated teachers should only report for work 20 minutes before class starts and leave 20 minutes after the school day ends. They had started phasing out the campaign on Monday, following the tentative deal.