TOKYO (AFP) - Tokyo's Nikkei stock index jumped 3.01 per cent Wednesday as bargain-buying and a weaker yen lifted the Japanese market, following a rise on Wall Street bolstered by strong US corporate earnings.

The benchmark Nikkei 225, which tumbled 7.3 per cent last week, added 420.87 points to finish at 14,417.68, while the Topix index of all first-section shares tacked on 2.68 per cent, or 30.46 points, to 1,166.55.

Bargain-hunting helped drive Tokyo's strong gains, while shares of market heavyweight SoftBank soared 8.50 per cent to 7,604 yen.

The jump came after Chinese e-commerce giant Alibaba - in which SoftBank owns a 37 percent stake - said fourth-quarter profit more than doubled to over US$1.3 billion (S$1.6 billion).

"There is some buying in baskets of stocks seen oversold after the steep sell off we saw last week," said an equity trading director at a foreign brokerage.

The yen declined - which boosts exporters' profitability - as Bank of Japan governor Haruhiko Kuroda said the country was on track to reach a 2.0 per cent inflation target as Tokyo works to reverse years of falling prices and tepid growth.

In afternoon trading, the dollar rose to 102.25 yen from 101.94 yen in New York Tuesday afternoon.

The Nikkei's Wednesday gain followed a rise of 0.62 per cent on Tuesday, but analysts warned that the market's upside was less than solid.

"The Nikkei staged a minor bounce on Tuesday, but participation is not at the point where one could say traders are suddenly bullish," said Daisuke Uno, strategist at Sumitomo Mitsui Banking Corp.

Chinese data published Wednesday showed first-quarter growth slowed to 7.4 percent on-year, its lowest level in 18 months, but it had little impact on the Japanese market.

"The numbers were close enough to be called 'on target', but they're not exerting much influence on Japan shares today," Kenichi Hirano, market analyst at Tachibana Securities, told Dow Jones Newswires.