The application deadline is March 31 and the number of founding members will be confirmed on April 15, Foreign Ministry spokesperson Hua Chunying said.
Until today 30 countries have passed the "multilateral examination procedure" and become the prospective founding members, she told a media briefing here.
Some applicant states are still undergoing a multilateral review process, she said.
State-television said about 45 countries so far applied for membership. The latest countries to apply are Sweden and Australia.
More From This Section
Meanwhile, Taiwan caught China by surprise by applying to join the AIIB, while reports said Beijing may not be considering North Korea's application to join it.
Responding to the questions, Hus said "as per Taiwan joining the Bank we maintain that we should avoid two Chinas and one Taiwan and One China situation", she said.
China officially considers Taiwan as its part and consistently opposed other countries extending diplomatic recognition.
Taiwan is not a member of the United Nations, World Bank or International Monetary Fund.
While Japan today declined to join the new Bank citing concerns over debt sustainability, environmental safeguards, US kept China guessing as Treasury Secretary Jack Lew who held talks with Chinese officials here yesterday promised American cooperation for the new Bank but no announcement has been made so far.