TORONTO - The union representing Ontario's public high school teachers says most of its bargaining unit heads have endorsed contract changes reached with the provincial government late last month.

The Ontario Secondary School Teachers' Federation says bargaining unit presidents voted 96 per cent in favour of the tentative deal at a meeting Thursday in Toronto.

Full details of the agreement -- which will be voted on by teachers between now and April 18 -- were not released.

Government sources have said younger high school teachers will be given a much better payout for their banked sick days under the agreement with the minority Liberal government.

The sources said teachers with less than 10 years on the job will get 25 cents on every dollar for sick days they banked, compared with 10 cents under existing agreements.

The union and Premier Kathleen Wynne have insisted the updated tentative agreement would not cost the province any additional money.