All 17 public high schools in Niagara will be closed Wednesday, part of a province-wide, one-day walkout by workers represented by the Ontario Secondary School Teachers' Federation (OSSTF).

The District School Board of Niagara (DSBN) announced the closures, which include schools in Niagara Falls, St. Catharines and Welland, Tuesday evening.

Elementary schools with the board will not be affected, but five French schools in Welland, three in St. Catharines, three in Niagara Falls and 1 in Port Colborne will also be closed.

Kim Yielding, spokesperson for the DSNB, said the board is encouraging students to use the day off to study.

"We would love it if students would spend the day off maybe reviewing their work from the semester, preparing for upcoming exams."

She added any information that would have been taught during the school day will be covered in classes to come so students will be "well-prepared by their teachers and ready to write their exams."

Clubs and after-school sports are also cancelled.

The strike comes after months of negotiation between the union and Ministry of Education.

OSSTF president Harvey Bischof said last week the union continues to plan strike action to protest growing class sizes, mandatory e-learning and as well as a lack of support for vulnerable students.

On Tuesday he tweeted that Education Minister Stephen Lecce "rejected" the union's offer to delay the strikes if management agreed to 2018/2019 staffing levels.

Sadly, <a href="https://twitter.com/Sflecce?ref_src=twsrc%5Etfw">@Sflecce</a> rejected our offer to delay the <a href="https://twitter.com/hashtag/OSSTF?src=hash&ref_src=twsrc%5Etfw">#OSSTF</a> strike in some boards tomorrow if the management team agreed to return to 2018/19 staffing levels for teachers & ed workers. Clearly this gov't wants to continue to erode the quality of education in Ontario. <a href="https://twitter.com/hashtag/onted?src=hash&ref_src=twsrc%5Etfw">#onted</a> <a href="https://twitter.com/hashtag/onpoli?src=hash&ref_src=twsrc%5Etfw">#onpoli</a> —@HarveyBischof

For his part, Lecce called the threat of a strike Wednesday "unfair to students and their families."

According to Lecce, the sticking point between the union and province is a wage increase.

OSSTF's last contract with the province expired Aug. 31.

Wednesday's job action would be the fourth walkout in just over a month.