Ontario's elementary teachers have ratified a new central contract agreement with the provincial government, bringing a formal end to their work-to-rule campaign.

Members of the Elementary Teachers' Federation voted 86 per cent in favour of the deal, while 98 per cent of union locals also voted to accept the tentative agreement reached Nov. 2. Under ETFO's "double majority" voting process, both union members and union locals must vote to ratify the central agreement.

"While this round of bargaining was exceptionally lengthy and difficult, ETFO members pressed for improvements related to student learning conditions such as special education, class size and composition, teacher professional judgement and health and safety issues," ETFO President Sam Hammond said in a release.

ETFO was the last of Ontario's four big teachers' unions to reach a new contract agreement, but the government insisted all of them were "net zero" deals, meaning any wage increases had to be offset by savings found elsewhere.

Those earlier agreements with unions representing high school teachers, Catholic teachers and their colleagues in the province's French school system included pay raises of 1.5 per cent plus another one-per-cent bonus.

Education Minister Liz Sandals has said the key elements in the ETFO agreement, such as salary, are similar to those ratified earlier by the other teachers' unions, but details have not been made public.

ETFO said its agreement calls for a review of full-day kindergarten staffing and class sizes, another review of class sizes in Grades 4-8, and promises to help develop recommendations to better support students with special needs.

"Class sizes in FDK, junior and intermediate grades that are in line with those at the secondary level...should be priorities for the government and school boards on an ongoing basis," said Hammond.

ETFO's 78,000 members began job action in May, escalating a work-to-rule campaign in September and again last month when they withdrew from extracurricular activities, but they never engaged in one-day rotating strikes as threatened.

All the teachers' unions must also reach local agreements with school boards under the new, two-tier negotiating process introduced by the Liberal government for the latest round of bargaining.

It took more than a year after their last contracts expired to reach the new central agreements, and the Liberal government is under fire for giving three teachers' unions a total of $2.5 million this year to offset negotiating costs.

The Liberals agreed to have Ontario auditor general Bonnie Lysyk examine a total of $3.74 million government payouts to teachers' unions since 2008 that were to help cover their negotiating costs.

Sandals said she's "quite confident" there was no problem with the payments to the teachers' unions, after she changed her earlier position and said the unions will have to account for how they spend the money.

ETFO had said it would not accept any such payment, and Sandals this week denied published reports that the elementary teachers' union was getting a special $600,000 payment to cover negotiating costs.

The auditor general is expected to present her report by the spring of 2016.