The quake struck at 6:52 p.m. Friday (1052 GMT) in Hubei province with its epicentre near Sanligang township about 200 kilometres (120 miles) north-west of the dam, the China News Service reported.
The quake was felt in Yichang city near the dam, where local residents said buildings rocked and objects in their homes rattled and moved, it said.
"This earthquake will not have any damaging effect on Yichang city or the Three Gorges Dam," the service quoted a provincial earthquake official as saying.
Immediately after the earthquake local seismologists began emergency monitoring procedures to inspect and monitor for possible damage, it said.
According to the Beijing News, on October 15 a quake measuring 3.0 on the Richter scale struck the region around Sanligang township, while 10 smaller tremors have rattled the area during the last 15 days.
The Three Gorges Dam is the world's biggest hydroelectric project and is expected to provide China with electricity for decades to come, while working to control floods in the middle reaches of the Yangtze river, China's longest.
Nearly 1.1 million residents were forcefully moved out of the historic and scenic Three Gorges to make way for the project which is expected to have a lasting environmental impact on the region and river, opponents to the controversial project have said.
Concern about earthquakes in the region was also a key argument against the dam, which was completed this year, but will reach its full electrical output capacity in 2009.

Copyright AFP (Agence France-Presse), 2006