Do you want fries with that? Too bad, says KFC Japan

Kentucky Fried Chicken in Japan has stopped selling fries, as industrial disputes that have crimped potato exports from the US took another bite out of the country's fast food market.

The chain became the latest casualty of the chip shortage that has already forced McDonald's Japan to ration its servings.

"Due to the prolonged dockworkers' disputes on the United States West Coast, it has become difficult to secure stable supplies of potatoes," the firm said in a statement dated Thursday.

"The company will halt the sales of potatoes temporarily until a stable supply becomes available."

Chip troubles for "The Colonel" came after McDonald's in Japan said last month it had airlifted in more than 1,000 tonnes of potatoes and had put in place emergency shipment via an unusual sea route.

The airlift eased the shortage that had forced the chain to limit customers to small servings of fries.

That came after the operator of the Gusto restaurant chain also said it planned to airlift in around 200 tons of french fries to avoid running short.

Dockworkers in the US are reportedly on a go-slow and have not been providing full crews for months in a bid to gain bargaining leverage in labour negotiations with employers.