Micro blogs have brought new challenges for government as it responds to emergencies and fights to gain the upper hand in solving social problems, experts said.

"Micro blogs have virtually created a competitive relationship between the government and the public for dominance after some public events happen," said Wu Hui, a professor at the Party School of the Communist Party of China Central Committee.

Wu said the faster the government responds, the higher the possibility that it will win public understanding and support, and the chances for rumors will be reduced.

"Weibo has almost shortened the principle of responding within the 'golden 24 hours' to within an hour after emergencies occur," said Li Weining, deputy director of the institute of public opinion on the Internet under the Communication University of China.

But Li said the government is lagging behind in the ability to deal with emergencies on weibo.

"Seen from recent Internet sensations, the failure of government agencies has contributed to some incontrollable consequences of online public opinion," he said.

One day after a high-speed train rammed into a stalled train near Wenzhou, Zhejiang province on July 3, which left 40 dead and 191 injured, more than 3 million messages about the accident were sent on Sina, but no official statement was seen on the platform.

Government weibo will inescapably be the focus of the public for chasing developments after some incidents.

Some officials perform well in responding to public issues on weibo, and Du Shaozhong, deputy director of Beijing municipal environmental protection bureau, is one of them.

"I will give more feedback to the voices of doubt, and expand communications beyond the Internet," he said.

Zhu Huaxin, an analyst from the public opinion supervision department under people.com.cn., recognizes Du's acheivements.

"Smog and air quality in the capital has been a hot topic recently. He frankly talks with netizens and listens to their voices, including scolding and complaints," he said.