Unifor is set to provide an update on contract negotiations with General Motors.
National President Jerry Dias has a virtual news conference scheduled for 10 a.m. tomorrow via Facebook Live.
The union is negotiating on behalf of 1,700 members working in St. Catharines, Oshawa, and Woodstock.
The strike deadline is 11:59 p.m. tonight.
The union previously reached deals with Fiat Chrysler and the Ford Motor Company.
Part of the deal with Fiat included a $1.5 billion investment in electric vehicles.
The Ford negotiations yielded a $1.95 billion pledge to retool the Oakville location to build five models of electric vehicles.