Seoul: Showing optimism in Japan’s market, US billionaire investor Warren Buffett said that a massive natural disaster would not spoil the future of Japanese economy and could speed up a new bout of stock buying.

Buffett, the chairman of investment firm Berkshire Hathaway, was visiting South Korea to attend a ground-breaking ceremony for a local unit of Israel's Iscar Metalworking Companies, 80 per cent owned by Berkshire Hathaway.

Japan's Nikkei index lost around 10 per cent in the week following the devastating March 11 quake and tsunami.

Buffett, however, urged against selling Japanese stock and said Japan would recover relatively quickly. Markets were closed in Tokyo on Monday.

Buffett, known as the "Oracle of Omaha" for his investment savvy, said Berkshire was seeking further acquisitions worldwide including South Korea following its USD 9 billion purchase of US lubricant maker Lubrizol.

"We're looking at a number of big businesses in Korea, the US, and the UK. We hope to find good companies wherever they may be. Basically, it's the bigger, the better," he said.

The catastrophe, which has left 8,649 people dead and 13,262 missing, could cost the Japanese economy up to USD 235 billion, the World Bank said on Monday.