The planned authorized capital of the Asian Infrastructure Investment Bank (AIIB) is $100 billion, and the proportion that will be contributed by countries in Asia will be decided based on their comparative GDP levels, Shi Yaobin, China's vice minister of finance, was quoted by the Xinhua News Agency as saying on Friday.

As for economies outside Asia, GDP will also be an important criterion for deciding on the amount they should contribute, Shi said.

GDP size is also an important factor in deciding on contributions from member countries of the IMF and the World Bank.

The contribution to the bank's capital from each member will likely affect their voting power at the AIIB.

Shi's remarks indicate the AIIB's founding members will be divided into two parts between Asian countries and economies outside the region.

Differentiating Asian countries from nations outside the region will help to give emerging market economies in Asia a stronger voice at the bank.

So far a total of 57 countries have joined the AIIB as prospective founding members, including 20 from outside Asia. The 20 nations - mainly composed of developed economies such as the UK and Germany, which have large GDP levels - may be granted more voting power at the AIIB if they are put in the same group with Asian countries.

The current allocation system will help ensure more voices can be heard from Asian countries so that financing for their infrastructure requirements can be provided, which was the original reason for setting up the bank.

The system means that the bank will stick to its role as a supplement to the World Bank because it will focus mainly on Asia, which is currently struggling to find enough financing for its many infrastructure projects.

Asia needs about $750 billion in financing every year to support infrastructure construction, and the Asian Development Bank (ADB) and World Bank can only provide about $10 billion each in loans per year, according to experts. The current contribution system will help the bank meet the huge investment needs.

China and India are likely to become the first- and second-biggest shareholders in the AIIB, given the two countries' economic prominence in Asia.

The shareholding ratio will be decided based on economic factors and without political interference, signifying that the AIIB will be operated according to business principles alone.

The bank, initiated by China in October 2014 to spur infrastructure investment in Asia, has been seen by some Western media outlets as a rival to the Western-dominated World Bank and the Japan-led ADB, and some Western scholars have also said the AIIB could undermine the two countries' regional standing in Asia.

However, this is not true, because China has said the AIIB is open to the US and Japan and the two economies were welcomed to join the bank as founding members.

The current contribution system means that Japan would have become the second-largest shareholder in the AIIB if it had joined as a founding member. The US would also enjoy large voting power in the bank as it is the largest economy outside Asia.

The author is a reporter with the Global Times. bizopinion@globaltimes.com.cn