Furloughs affect Unifor members who are not on strike but who work at CN’s Halifax facility.
Cuts are expected to result in monthly cash savings of about $400,000.
Local Unifor president fears more job losses beyond the initial layoffs as the contracts wind down.
GM targeted the plant because of flagging demand for the subcompact Cruz sedan.
The company hasn’t said how many employees were laid off.
Last November, the plane-and-train-maker announced about 5,000 layoffs.
The profits are being announced as GM lays off thousands of workers.
US company plans to close its plant in Quebec City and distribution centre in the Montreal area next September.
Closures to take place by year-end will affect about 65 workers in Barrie and Peterborough.
About 215 people to go, adding to the 340 job cuts from the factory in July.
Closings are part of a cost-cutting plan as the company tries to wrangle falling sales.
Cuts would target salaried employees, reduce global headcount by 10%.
Most of the layoffs will come from hourly employees outside of the US.
Province facing a big drop in revenue from oil and gas, potash and uranium.
Automaker says moves are meant to align production to demand for the cars.