SINGAPORE, April 11 -- China and all the member countries of the Asian Infrastructure Investment Bank (AIIB) will be committed to building a bank which would be lean, clean and green, said Jin Liqun, secretary general of the interim multilateral secretariat of the China-proposed institution here in Singapore on Saturday.

Jin made such remarks at the two-day "Singapore Forum 2015" which concluded Saturday.

"Lean is cost effective; clean, this bank will have zero- tolerance on corruption; green means it's going to promote the economy," he said.

The bank has seen more than 40 prospective founding members by Saturday, with Spain, South Korea and Austria as the most recent prospective founding members.

Talking about whether the increasing number of members would add difficulty on the decision-making process of the AIIB, Long Yongtu, China's former vice trade minister who also attended the forum, told Xinhua that the more countries joining in, the stronger the foundation of AIIB would be.

"Everything has two sides. It would pose some difficulty to the coordination of the positions and interests of all the member countries, especially many of which are at different economic level of development. But it is definitely not good news if the AIIB earned little response."

"AIIB is not the first multi-lateral financial institution, and we have a lot of experiences to borrow," Long added.

His words were also echoed by Jin. "World Bank and Asian Development Bank (ADB) have been operating for decades, and they have gained a lot of experiences in supporting the investment in other countries," he said.

But he also pointed out the difference between the AIIB and the existing institutions.

"China itself benefits enormously from the contribution by World Bank and the ADB. Now it's time for China to do something more for this region. And the difference between AIIB and World Bank and ADB is that this bank focuses exclusively on infrastructure development."

Talking about the operation of the bank, Jin said the bank would not be operated politically, but professionally.

"AIIB is a bank, not a political organization or political alliance. This guaranteed that it would be impossible to operate it in an untransparent way," he said. "AIIB is not China's bank. Many people have put too much emphasis on politics; this is a misunderstanding towards AIIB," said Long.