Japanese shares gained on Wednesday after a central bank survey showed big businesses intended to increase capital spending at their fastest pace in a decade, but caution over developments in Greece limited gains.

Confidence at big Japanese manufacturers unexpectedly improved in the second quarter and is seen rising further, the Bank of Japan's "tankan" survey showed, offering relief to policy-makers keen to jump-start the economy.

The Nikkei share average rose 0.5 per cent to 20,329.32. The broader Topix gained 0.4 per cent to 1,636.41 and the JPX-Nikkei Index 400 climbed 0.3 per cent to 14,764.55.