Restaurants in Japan are rushing to secure supplies of french fries after shipment delays from the US, with one chain readying to airlift 200 tons of chips.
Giants of the fast food and "family restaurant" sectors, which serve Western style meals with a Japanese twist, are dependent on imports, Kyodo News reported, citing the chains and the Japan External Trade Organization.
But a dockworkers' dispute on the US West Coast has caused a months-long slowdown, creating a backlog and crimping imports to Japan.
The Japanese arm of McDonald's has been having problems since mid-November, Kyodo said, while Royal Holdings, which runs several family restaurant chains, said it has a few months' worth of stock, but was keeping a close eye on things.
Meanwhile, the operator of the Gusto chain said it planned to fly in around 200 tons of french fries to avoid running short, the agency reported.
News of the chip woes came with Japan already in the throes of a butter shortage that is threatening to ruin Christmas for millions of cake-baking Japanese housewives.
Supermarket shelves have been empty for weeks, with any new stock disappearing almost as fast as it arrives, despite store-imposed limits of one pack per customer.
However, there was a glimmer of hope Thursday, with the farm ministry announcing four of Japan's major butter producers would up their output by a third to meet demand.
"Sufficient supply of butter will be ensured at stores before the Christmas season," a ministry official said.
The ministry earlier said a sweltering summer had left the nation's cows exhausted, and sapped their milk-producing ability.