Workers involved in a labour dispute which threatened to close the Stellantis assembly plant in Windsor, Ontario have returned to work as negotiators continue trying to resolve a contractor issue, a media report said.

"Former AWC Unifor workers are back on the job as Stellantis and Unifor continue discussions. Regular production continues at the Windsor Assembly plant," Stellantis said in a statement cited by TheDetroitBureau.com.

The report said a barricade had been put up by members of Canadian auto workers union Unifor which threatened to halt plant operations. The line was put in place after the company replaced a Unifor-represented contractor, Auto Warehousing, with a different company. AWC marshalled new vehicles rolling off the line for shipment and the change affected about 60 members of union branch Local 444.

TheDetroitBureau.com said the automaker and union agreed to resume talks after a Canadian labour court declined Stellantis' request for an order that would have forced the Unifor members to remove the barricade at a gate used for employee access and shipping finished vehicles from the plant.

All employees represented by Unifor, however, have now returned to work, Dave Cassidy, Unifor Local 444 president, reportedly in a video on the branch's Facebook page.

"It's been gut wrenching over the last couple of weeks," Cassidy said. "The former AWC workers of Local 444 are back on the job as FCA and us work over the next little bit to sort out the fine details around it," he said, noting he had spoken with senior executives as part of the effort to resolve the dispute.

Shutting down the plant is a massive issue for Stellantis, which just debuted publicly Monday after more than year of merger talks, TheDetroitBureau.com said.

The automaker has been hit with the unscheduled shutdown of the assembly plant in Brampton, also in Ontario, where it builds the Dodge Challenger and Charger. That shutdown was triggered by a shortage of critical computer chips, and is due to stretch to the end of January, company officials told TheDetroitBureau.com.

The report said the new contractor, a firm called Motipark, does not employ Unifor members, but Local 444 maintains, under Canadian law, AWC employees have successor rights to the jobs on the Stellantis property.

Space to store production around the plant was close to exhaustion at the sprawling Walker Road facility, according to the report, citing the Windsor Star.

The resumption of negotiations also followed Stellantis' failed appeal to the Ontario Labour Relations Board. Stellantis maintained the blockade amounted to an illegal strike, but the board sided with Unifor, TheDetroitBureau.com.

Stellantis had also warned Unifor its members wouldn't get paid if the dispute stopped production. Cassidy, however, noted no production was lost. The board's ruling prompted another round of discussions between company and union representatives, the report added.

Windsor builds the Chrysler Pacifica minivan range while Brampton is home to the Chrysler 300 and Dodge Charger and Challenger.