The Japanese government on Monday revised upward its estimate of economic growth in the first quarter, saying that the world's No. 3 economy expanded by 4.1 percent compared with the first three months of 2012.

Officials' initial report, released last month, said gross domestic product climbed 3.5 percent on an interannual basis in the January-March period.

The new estimate also shows that Japan's GDP grew by 1 percent in the first quarter compared with the last three months of 2012, its biggest quarterly gain in a year.

Investors in the Tokyo stock market reacted enthusiastically to the revised growth figure, pushing the benchmark Nikkei index up by 5 percent.

Some analysts, however, are waiting to see the second-quarter numbers before making a judgment on the economic program of Prime Minister Shinzo Abe, dubbed "Abenomics," which includes much looser monetary policies and increased infrastructure spending.

"It is hoped that the improvement in business profits boosts households and strengthens consumption," the Daiwa research institute's Mitsumaru Kumagai told Kyodo news agency. EFE