A morality bank in a northeastern Chinese city has seen residents flocking to open accounts that enable them to exchange good deeds for free services.

Citizens in Yanji City, Jilin Province, can accumulate credits with the bank, operated by Danying Community, through tasks such as collecting plastic bags off the streets (10 points), handing in lost wallets (50) and donating blood (200).

Top credit earning deeds include helping others in a dangerous situation (300-500 points) and donating hematopoietic stem cells (1,000 points).

Credits can be exchanged for rewards such as a free haircut (150 points), home cleaning (500) or a health check (1,200). People who collect more than 6,000 points will win the accolade "Models of Community Morals."

Over 600 citizens have opened accounts since the bank was established on May 14, said Wang Shuqing, a community official. "The phones have not stopped ringing," she said.

Emerging as a novel way to encourage kind acts in 2002 in several Chinese cities including Changsha and Wenzhou, morality banks have their critics, who say the program sullies good deeds because of the materialistic nature of the scheme.

A college in central Hunan Province in 2007 also courted controversy by linking morality bank accounts with the performance evaluation of its students.

However, proponents argue that rewarding good deeds is important in a society allegedly struggling with a "moral decline".

"It is meaningful to record good people and good deeds with these moral points and use them as a standard for reward," said Zhang Yanyan, a local resident who opened the account.