Ontario elementary school teachers will launch some form of strike action on Monday, which would affect hundreds of thousands of students across the province.

On Tuesday, the Elementary Teachers' Federation of Ontario (ETFO) issued a news release saying its workers "will be taking provincewide strike action as of Monday."

The night before, the ETFO, which represents some 76,000 teachers, also sent out a series of robocalls advising teachers that the union is considering its options when it comes to what a strike could look like.

Some 800,000 students could be affected if Ontario elementary teachers, represented by ETFO decide to take a form of strike action Monday. (Larry Downing/Reuters)

ETFO president Sam Hammond told CBC News that parents will be told what they can expect from the job action by Thursday night or Friday morning.

"We are not going to comment on strike action details publicly until we've had an opportunity to communicate with all our members this week," Hammond in the earlier news release.

However, a confidential memo obtained by CBC News shows that the union plans to start work-to-rule on Monday.

The memo says the job action "won't impact student programs, extra-curricular initiatives and field trips, but it will affect Ministry of Education initiatives."

School boards have been rushing to reassure parents that classes will not be cancelled.

Teachers concerned about concessions

The ETFO's job action comes after eight months of fruitless negotiations with provincial representatives, Hammond said.

"We haven't seen any progress at that table," he said.

"We need them to take us seriously. We find the concessions that they've put on the table offensive."

Hammond said under those concessions:

Teachers would lose control of their own preparation time.

Teachers would continue dealing with an "excessive" number of ministry initiatives.

The government would rescind Regulation 274, which allows occasional teachers to be hired into long-term or permanent contracts.

Hammond said the province needs to remove those concessions before the union returns to the bargaining table. Salary discussions — it's believed the government will seek a wage freeze — have not been happening at this time, Hammond said.

Teachers join wave of unrest

ETFO recently received a "no board" report from the province's Labour Ministry, signifying the two sides are at an impasse when it comes to renegotiating teacher contracts.

The teachers' current contract expired last August, the union said.

Part of the difficulty with this bargaining stems from the new two-tiered system, in which teachers' unions negotiate with both local boards and the province in parallel talks.

If the teachers actually walk off the job, they would join other striking teachers in Ontario: