No Chinese citizens had been reported injured or dead in Monday's earthquake, Foreign Ministry spokesman Liu Jianchao said in Beijing yesterday.
Liu told a regular press conference the Chinese government would keep in touch with Indonesia and closely track developments in the disaster-hit areas.
China will give US$500,000 in cash for relief work.
President Hu Jintao sent a condolence message to Indonesian President Susilo Bambang Yudhoyono.
Foreign Minister Li Zhaoxing also sent a condolence message to Indonesian Foreign Minister Hassan Wirajuda, Liu said.
"We are deeply sympathetic to the Indonesian people ravaged by the disaster and would like to express our sincere condolences to the victims," Liu said.
He said the Chinese government and the Red Cross Society of China are considering providing emergency relief materials to the victims.
China's monitoring station in its southernmost city, Sanya, detected waves 4 to 5 centimeters high early yesterday, proving the quake caused a very small tsunami.
"The tsunami had very little impact," said Ye Lin, a chief forecaster with the State Oceanic Administration.
After the December 26 tragedy, China established an automatic early-warning tsunami system which started operation on February 8 and has received more than 20 alerts from the Pacific tsunami warning center.
"The system can tell us what kind of influence a tsunami has on China's sea areas," Ye said.
China has formed a wave-monitoring network with more than 50 coastal stations which collect data of storm tides once an hour and which would rise in frequency to once a minute if a tsunami was to take place.