Thailand signed the Asian Infrastructure Investment Bank (AIIB) Agreement here Tuesday, the Chinese Ministry of Finance (MOF) announced Wednesday.

Thailand is the 52nd of 57 prospective founding members to sign the document. The others are still waiting for administrative approvals at home.

After signing the agreement, all of the 57 members must get the green light from their legislatures by Dec. 31, 2016, before becoming a founding members of the bank.

"All the prospective members are now pushing to quicken the legal procedures so that the AIIB can be established before the end of 2015," said the MOF.