The Toronto District School Board is asking the province to extend its deadline for an agreement to be reached between the school board and the union representing high school teachers.

The TDSB wants to give teachers a chance to vote on the latest deal, which offers a 12.55 per cent raise over four years along with enhanced benefits and more teachers, the board says. The request, however, was denied.

The Ontario Secondary School Teachers' Federation has not accepted the Toronto board's latest offer, the TDSB said in a statement.

If an agreement isn't reached by Thursday, the deal will be pulled and teachers will have to settle for a four per cent raise over two years.

Supervision time has been a major sticking point in the negotiations.

Teachers under OSSTF District 12 are the only in Ontario that have not reached an agreement.