Ontario English public high school teachers have reached a tentative agreement with the province and public school boards, but it's unclear if the deal will speed negotiations with other unions and avoid job action with the school year now less than three weeks away.

The Ontario Secondary School Teachers' Federation (OSSTF) returned to the bargaining table on Wednesday and struck a deal within 24 hours, according to a news release.

The tentative agreement must be endorsed by each local sector of the union before it becomes official. Those leaders are expected to meet in the coming days, the OSSTF says in the release.

Premier Kathleen Wynne said it was a challenging negotiation, but collaboration prevailed.

"This is a very significant and happy day in terms of getting our kids back to school," she said.

"I know our teachers want to be in school, I know our support staff want to be in school, and our kids want to be in school — they may not know they want to be in school but they do want to be in school — and certainly their parents want them in school learning, so this is a great step."

Education Minister Liz Sandals said Thursday she's happy a deal has been reached with OSSTF.

"Negotiations were challenging for all sides, but it speaks to the dedication and commitment of everyone involved that collaboration prevailed and a tentative agreement was reached," she said in a statement.

Sandals said the government is working to get deals with other unions for teachers and education workers "throughout the remaining weeks of the summer in order to reach agreements at all tables."

OSSTF president Paul Elliott said key to breaking the "logjam" was the premier's office becoming involved earlier this month, and management's willingness to take certain sticking points off the table.

Other unions still working out deals

Other unions still don't have agreements for the upcoming school year.

They include the:

Elementary Teachers Federation of Ontario ( EFTO ), with 76,000 members.

), with 76,000 members. Ontario English Catholic Teachers Association ( OECTA ), with about 50,000 members.

), with about 50,000 members. Association des enseignantes et des enseignants franco-ontariens ( AEFO ), which represents about 10,000 teachers and workers in Ontario's French-language schools

The ​OECTA Is scheduled to resume bargaining Thursday. The ETFO doesn't return to the table until Sept. 1.

Hours after the OSSTF deal was announced, ETFO president Sam Hammond outlined how his members would begin working to rule if a deal is not reached by the time the school year resumes. Hammond said his members will not take part in field trips, respond to emails from principals outside of school hours or take part in parent-teacher nights until a deal is reached.

​Wynne said the OSSTF deal makes her optimistic about reaching deals with the other unions. She added there are similar issues at each table, but would not go into details about the deal or the other negotiations.

'Net zero' among sticking points

Details of the tentative deal struck early Thursday have not been made public.

CBC Queen's Park reporter Mike Crawley reported last week that sticking points in negotiations included the province's demand for "net zero" wage increases, which means that any wage hikes would have to be offset by wage savings in other areas, such as days off without pay. Teachers and school boards also wanted more wiggle room on hard caps on class sizes.

Elliott said the next step is for the union — which represents 60,000 teachers, educational assistants and support workers — to take the deal to local union presidents across the province in a meeting later this week. After that, he expects a ratification process that likely won't wrap up until mid-September.

He said the OSSTF deal could help clear the way for agreements with the other unions, but said "there are some different issues at the different tables."

No new money for salaries

Wynne has said the government will not fund any salary increases for civil servants or anyone in the broader public sector — more than one million Ontario workers — until it eliminates an $11.9-billion deficit, which it plans to do by 2017-18.

The unions have warned of co-ordinated job actions if there are no new agreements when classes resume, but none is threatening a full-scale strike.