TOKYO, April 8 -- Japan has indicated that it remains interested in joining the China-proposed Asian Infrastructure Investment Bank (AIIB) with local media reporting Wednesday that the government had earmarked 1.5 billion U.S. dollars as its contribution.

The government here has prepared a draft document on the possibility of its joining the AIIB, which is scheduled to be launched by the end of the year, with the document suggesting that Japan still has some issues pertaining to the bank's governance.

But Prime Minister Shinzo Abe, according to sources close to the Japanese leader Wednesday, is strongly considering green- lighting Japan joining the China-led initiative and is currently and further evaluating the prospect.

Sources familiar with the matter said that Japan's initial investment of 1.5 billion U.S. dollars was based on an assumption that of the 50 billion U.S. dollars initial capitalization of the bank, 10 billion U.S. dollars would come from direct investments from potential members.

Japan's investment was calculated taking into account the nominal gross domestic product of the bank's potential participants with 75 percent of the payments coming from Asian economies being used as a benchmark, the sources said, adding that 25 percent of the payments would be coming from non-Asian economies.

Japan, who hold China as its biggest trade and economic partner, hopes that its joining the AIIB could help improve ties between Tokyo and Beijing, which have soured of late owing to issues of territory and history.