TORONTO -- The union representing Canadian workers at General Motors says it has reached a tentative agreement after extending negotiations with the automaker.

Unifor had set a deadline of 11:59 p.m. on Wednesday to reach a new, three-year labour deal and encouraged members to be prepared to strike if needed.

But the union said just before the deadline that its master bargaining committee was ready to negotiate all night to avoid a work stoppage.

The announcement of the deal, which still needs to be approved by GM's union members, came about four and a half hours after Unifor said it would extend the deadline for the labour talks.

The vote is scheduled to take place Sunday.

Unifor said the deal is being unanimously recommended for 1,700 members working at GM plants in the southern Ontario cities of  St. Catharines, Oshawa and Woodstock.

The Detroit automaker did not immediately provide a statement on the agreement.

Jerry Dias, Unifor's national president, is expected to give more information at a news conference at 10 a.m. ET.

The union said on Wednesday afternoon that executives from GM came to Canada this week for face-to-face discussions as bargaining heated up.

Ahead of the deadline, the union said the company had not offered concrete commitments on future product plans, and was falling short of earlier agreements struck by Ford Motor and Fiat Chrysler Automobiles.

Those deals, which were announced and voted on last month, will phase in about 2,000 new jobs over the next few years, helping the company bounce back from staffing cuts over recent months.

Fiat Chrysler Automobiles has said $14.4 million will be invested in its Toronto plant, $50 million will be invested in its Brampton, Ont., plant, and $1.35 billion to $1.5 billion will be invested in reinventing its Windsor, Ont., plant to produce at least one electric vehicle.