Saskatchewan's largest potash producer will start sending hundreds of workers home on Friday.

Nutrien says 470 employees from its Vanscoy operation have been notified they won't be needed as of Friday due to production being halted.

Another 140 workers from the company's Allan property were notified they will be temporarily laid off as of May 6.

The company told CBC earlier in the day that 1,300 workers would be impacted.

Nutrien is blaming slow uptake of rail shipments from both sites for its decision.

"With the rail's limited operations, we want to get the product out, but if they can't get to our sites, and we can't get them out to our customers, then we can't really do anything with our product," said Will Tigley, a company spokesperson.

Rail slowdown also affects Mosaic

Nutrien isn't the only major Saskatchewan potash producer citing rail troubles.

Mosaic says that although it's not planning to issue temporary layoff notices, "our site warehouses are close to or at containment," said spokesperson Sarah Fedorchuk. "We have shifted maintenance work around to mitigate the impact."

Almost all of Mosaic's product — about eight million tonnes of finished potash per year — is shipped out by rail, according to the company.

"In addition, we have phosphate from our Florida operations coming to Canada. We have limited storage at the sites, measured in weeks of operating time, not months," said Fedorchuk.

"It is critical for our products to move daily by rail and we have been challenged this winter and spring to receive this level of service."