Nukaga met earlier on Sunday with his Chinese counterpart Xie Xuran and South Korean Finance Minister Kang Man-soo on the sidelines of the gathering, which is held outside of Asia every two years.
An agreement is expected to be announced after the finance ministers from the so-called ASEAN+3 group -- the 10 members of the Association of Southeast Asian Nations plus Japan, China and South Korea -- meet later on Sunday at the gathering.
The 13 nations agreed after the 1997-98 Asian financial crisis set up a bilateral currency swap scheme known as the Chiang Mai initiative to prevent a repeat of the turmoil.
At the ADB's last annual meeting in Japan in May 2007, they agreed to work towards a multi-nation scheme of currency swaps to make it easier to borrow emerge