TORONTO -- Elementary teachers in the Niagara region have announced a one-day walkout set for next week as the number of Ontario school boards targeted in rotating strikes increases.

The Elementary Teachers' Federation of Ontario says the District School Board of Niagara will be hit with a strike Tuesday.

The union says a one-day strike at the Keewatin-Patricia District School Board in northwestern Ontario will also take place that day.

Meanwhile, the Avon Maitland and Ontario North East school boards are set for one-day strikes Monday, while the Ottawa-Carleton District School Board says it will face a teachers' strike Wednesday.

The union says the walkouts are in protest of legislation that gives the government the power to stop strikes and impose collective agreements, measures the union says impede local bargaining.

Premier Dalton McGuinty has said he won't step in to block planned walkouts since they are only for one day and the union has promised to give 72-hours notice.

But Education Minister Laurel Broten says the government has prepared legal documents to cut short any strikes that stretch beyond one day.

Union president Sam Hammond called on Broten to give local school boards more freedom in bargaining.

"There are two solutions to the chaos that the minister of education has created," he said in a release Saturday.

"Along with repealing Bill 115, the minister needs to step aside and give locals the latitude to have concrete and respectful discussions with all options on the table, in order to reach collective agreements."