"The Arirang mass games have been cancelled," a Unification Ministry official said by telephone.

Leonid Petrov, who specialises in arranging tours to North Korea, said: "The official reasons named by the North Korean tourism authorities are the recent torrential rains and the planned joint military drill 'Ulchi Focus Lens', which will be performed by the US and South Korean military forces".

Petrov said the mass games festival will be moved to April.

North Korea typically objects to the annual joint drills, but it has not previously cancelled the mass games because of them.

About 100,000 people take part in the mass games -- called Arirang after a historic love story -- with some in the floor show and about 20,000 who make up a wall of flip-cards that forms the changing backdrop.

The games have increasingly become a source of foreign currency for the North.

Although the crowds are typically made up of North Koreans, the communist state sells thousands of tickets to foreigners, with prices ranging from 240 euros (US$306.30) for a box seat to 40 euros for a third-class seat.

In addition, visitors must buy a package tour where they spend several hundred euros a day for hotels, meals and guides.

Last year 7,000 tourists from South Korea attended. This year, the North was planning to open its doors to American tourists, with packages costing about US$5,000 to $6,000.

Three major storms hit North Korea in July, raising the possibility of famine in a country that already battles chronic food shortages, experts said.