Shinzo Abe has sent an envoy to Indonesia to offer a sweeter deal to build a high-speed railway, a Japanese Embassy official said on Thursday, highlighting the importance of the multibillion dollar project that China also wants to win.

The two Asian giants are in a neck-and-neck contest to win a contract to build Indonesia's first high-speed rail, between the capital Jakarta and textile hub Bandung, a project that would bolster their influence in Southeast Asia's biggest economy.

Japan and China have until Aug. 31 to submit their best offers to Jakarta.