One of the province's four teacher unions says some Sudbury's teachers will return to class in September with unfinished business.

The Ontario's Secondary School Teachers' Federation says the Rainbow District School Board still hasn't ratified a contract signed between the teachers and the province.

Teachers signed the memorandum of understanding with the province last April.

The memorandum tackles key issues that had teachers taking action last year, according to Paul Elliott, president of the OSSTF.

"[It] just sort of outlines our issues of how sick days are going to be dealt with … and other issues about how unpaid days are going to be dealt with. There's just a lot of issues like that that are in there," Elliott said.

School boards have until Aug. 29 to let the province know it will be appending the memorandum to the collective agreement.

Elliott said the union doesn't know what it will do if the boards don't acknowledge the agreement.

"We're not in a position where we can do any strike actions, so we're going to have to just find a way to put pressure on the boards for them to go ahead and do what the minister has really recommended all along."