"The economy of America, United States and others around the world are improving month-by-month," America's most famous investor, the so-called "Oracle of Omaha", said during his first visit to India.

"It might not be quite as fast as everybody would like but it is happening," the chairman of investment giant Berkshire Hathaway told India's CNBC-TV18 in an interview.

Buffett is in India to join Microsoft co-founder Bill Gates in seeking to persuade India's super-rich to part with some of their wealth as part of the "Giving Pledge" drive launched by the tycoons last year.

Gates and Buffett, who dined with Chinese billionaires on a similar mission last September, were to meet wealthy Indians on Thursday in New Delhi.

Buffett, known for his stock picking acumen, added global economies will only be "slightly affected" by the deadly earthquake and tsunami in Japan.