American food giant McDonald's has been forced to ration fries at its fast-food outlets in Japan as potato imports had fallen sharply due to Covid-19 and floods in Canada.

McDonald's Japan said it will only sell small-sized French fries for a week from Friday to avoid shortages, according to an AFP report.

"Due to large-scale flooding near the Port of Vancouver… and the global supply chain crunch caused by the coronavirus pandemic, there are delays in the supply of potatoes," according to a McDonald’s statement.

The fast-food giant said it has taken the measure to ensure that its customers can still get fries, amid the disruption in the supply chain.

The setback comes at a time when sales peak during the busy year-end holiday period in Japan.