Ontario secondary school teachers have reached a deal in principle with the provincial government after a long labour dispute that resulted in contracts being imposed by the government on public school teachers earlier this year.

"The government and [Ontario Secondary School Teachers' Federation] have been able to resolve implementation concerns identified in a number of areas including: sick leave, maternity leave, retirement gratuity, unpaid days, and local bargaining," said Education Minister Liz Sandals in a statement.

The deal was kept private for more than 48 hours, tweeted CBC's provincial affairs reporter Mike Crawley. Government sources told him a tentative deal with the OSSTF was reached around 4 a.m. Friday.

During the next several days, details of the "agreement in principle" will be shared with OSSTF members during the union's approval process, according to the statement.

The details will be made public after the OSSTF's process is completed. The provincial government and the teachers' federation have restored an important relationship, said the statement.

Deal criticized by Conservatives

Lisa MacLeod, MPP and the Conservative's education critic, released a statement responding to Sunday's developments, saying that although the Liberal government has not provided any additional details of the agreement, "it is already clear that the changes will be costly to the province which is in a massive deficit and already struggling to keep up with the increasing costs of frontline programs like full day kindergarten."

She called on Ontario Premier Kathleen Wynne "to tell the truth about what she has given away and what it will cost."

She said the agreement will cost parents, as it is likely to be extended to other teachers' unions.

MacLeod criticized Wynne for demonstrating to other public sector unions that "if they are unhappy with the province's fiscal parameters during or after negotiations they can count on her to give into their demands."

Turbulent relationship since Bill 115

Last September, the province passed anti-strike legislation, also known as Bill 115.

In the new year, the Ontario government used the new law to impose a contract on public and elementary secondary school teachers. The imposed contracts included:

Freezing wages for most teachers.

Reducing the number of sick days allowed.

Limiting the number of unclaimed sick days teachers can cash out upon retirement.

Public elementary school teachers then staged a series of rotating, province-wide, one-day strikes in December.

The province repealed Bill 115 in January after the two-year imposed contracts were in place. It was an act aimed as showing good faith to teachers.

Many educators remained angry and felt their rights to collective bargaining were curtailed by the government. Teachers unions asked their members to stop supervising extracurricular activities. Such supervision is outside their regular educator duties.

In late February, the OSSTF agreed to resume extracurricular supervision, leaving the choice of whether or not to participate up to individual teachers. The union president said at the time that the OSSTF was entering a "new stage" with the provincial government.