The People's Bank of China (PBOC), the country's central bank, will issue a set of gold and silver commemorative coins this month to celebrate the upcoming World Expo 2010 Shanghai (Series II).

In an announcement posted on its website, the central bank said the new Shanghai Expo commemorative series, consisting of two gold and two silver coins, are China's legal tenders and the issuance will start as of April 22.

The set of new coin series includes two gold coins diametered at 23 and 60 millimeters respectively, and two silver ones with a diameter of 40 millimeters each.

The smaller gold coin, with a face value of 150 yuan, contains one third of an ounce of gold and has a designated maximum circulation of 60,000. The bigger and more expensive 2,000-yuan gold coin contains five ounces of gold with a maximum circulation of 1,000.

Each silver coin contains an ounce of silver with a maximum circulation of 80,000 for both.

The central bank issued the Series I commemorative coins for Shanghai Expo in June last year and the new coin series will be distributed by the China Gold Coin Incorporation through its branches across the country.

The Shanghai Expo, believed to be one of China's greatest events this year, is due in China's economic hub of Shanghai from May 1 to Oct. 31 this year.