The Ontario Secondary School Teachers' Federation (OSSTF) announced Friday that it will hold another one-day strike in certain school boards on Dec. 18.

OSSTF President Harvey Bischof announced the latest job action in a statement that slammed Doug Ford's government for not changing its bargaining position.

"Since our last bargaining date on Tuesday, December 3, we have seen no change in the minister of education's agenda of increasing class sizes, forcing e-learning on our high school students, and continuing the funding cuts that take valuable support staff and services out of our schools," Bischof said.

Bischof said he's announcing the potential strike today to give parents five days to prepare.

"We are hopeful that the minister is ready to get serious about bargaining next week, to come to the table in good faith and reverse his government's devastating cuts to our students' education system," he said.

"That's what this fight is about, what it has always been about; this government's cuts to education will affect our students for not just one day, but for generations to come."

OSSTF says these school boards will be affected:

Lakehead District School Board

Thunder Bay Catholic District School Board

Lambton Kent District School Board

Thames Valley District School Board

Waterloo Region District School Board

Waterloo Catholic District School Board

York Region District School Board

York Catholic District School Board

Halton District School Board

Kawartha Pine Ridge District School Board

Several French school boards are also affected.

The labour action follows a one-day, province-wide walkout on Dec. 4, and a similar walkout in select areas in the province on Dec. 11.

The teachers have been without a contract since their last one expired at the end of August, and their union has blamed the Progressive Conservative government for the lack of progress in their negotiations.

Education Minister Stephen Lecce said in a statement Friday afternoon that the job action is all about salaries, benefits and "other entitlements.

"If there were any question that this wasn't about salary, those doubts were put to bed when the four teacher unions launched their challenge to legislation that deals with compensation increases for the public service," he said.

"We have made a reasonable offer on compensation — a $750 million increase in compensation for the second highest paid educators in the country. We are calling on OSSTF to cease from continued job action, accept our offer of private mediation, stay at the table, and focus on improving learning in the classroom, not enhancing compensation for their members."

A limited withdrawal of services that began on Nov. 26, will continue across Ontario, the union says.