The deadline has been extended for Ontario elementary school teachers to cast their ballots in a "political protest vote" expected to determine whether they hold one-day walkouts.

The 76,000 members of the Elementary Teachers Federation of Ontario began voting Sunday, and had been expected to close the online balloting by midnight Monday.

Instead, the union has added another 24 hours, with the vote now set to end at midnight Tuesday.

"Due to overwhelming demand, and to ensure that all ETFO members are able to exercise their right to cast a ballot, the voting period for ETFO’s full-day political protest vote has been extended," according to a statement posted on the union website.

Elementary teachers at some boards across the province are already involved in administrative labour action that effectively limits their work to the classroom and school hours.

At an after-school march and rally outside the Toronto District School Board offices Monday, Amanda Leah Jackson was among the crowd of elementary and high school teachers expressing their resolve to keep up the fight.

"We're 76,000 strong and we're going to keep fighting this government if they decide to take away our democratic rights to collectively negotiate our working conditions," Jackson told CTV Toronto.

Tara Stephen agreed.

"We're here for our democratic rights, it's very simple. We live in Canada and there's no point where we should be expected to just take something like this Bill (115) and not be able to vote and bargain freely."

Last week, the union issued a notice alerting elementary school students and their parents that they would be given 72 hours notice for "strikes planned for December."

"The strikes by ETFO locals will affect operations in each public elementary school throughout the province," the union said.

On Monday, the president of the Ontario Secondary School Teachers' Federation said his 60,000 members wouldn't be joining their elementary counterparts in strike action -- although they would step it up in other ways.

After meeting with members of local bargaining units, OSSTF president Ken Coran said high school teachers in the regular, Catholic and French boards would escalate their protest by arriving for and leaving from school within 15 minutes of their scheduled workday.

"Our members are fed up, we're tired of playing games," Coran said, telling reporters his union takes issue with the province's controversial legislation and its impact on teachers' rights, not the need to recognize budget concerns.

"It would be nice if the government would just listen to what we said: 'We are accepting of a wage freeze.' Let's repeal Bill 115 and this problem will go away."

In her own comments Monday, Education Minister Laurel Broten criticized union leaders for refusing to accept the province's fiscal reality.

"We would like to see our union leaders climb down from the precipice on which they are now standing and re-engage in local conversations. I am asking the union leadership to choose improvements for the kids over improvements for themselves," Broten said.

The unions have taken the provincial government to court over Bill 115, arguing the strike-limiting provisions of the provincial law passed in September violate teachers' rights.

Under the legislation, the unions and local school boards have until Dec. 31 to negotiate individual agreements to freeze salaries and scale back benefits, subject to the minister's approval. Failing that, the government can impose its own contracts in the new year.

The OSSTF announced last week it was stopping negotiations with local school boards, after two of three tentative agreements were rejected in ratification votes, and the minister withheld her approval to a number of others.

With files from CTV's Scott Lightfoot and The Canadian Press