The resulting splits and fissures occurring deep underground weakens hillsides and leads to the loosening of soil and rock, they say.
Last week, a bus was crushed under a landslide at Badong County in Hubei near a tributary to the dam, killing 31 people, including a worker on a nearby railway construction site.
Two more are reported missing.
Tuesday's statement is the latest government move to defend the Three Gorges project against claims that pollution and geological threats are piling up as waters rise and strain the brittle slopes surrounding the 660-kilometre reservoir.
In Tuesday's report officials said their monitoring showed the environment quality was "generally good" and that water and soil loss were "effectively controlled" in the construction and resettlement zones.
|The government said the loss of water and|
soil were under control [Reuters]
"No abnormalities have been discovered in the geologic environment," they added.
In a statement the project's construction committee said a "geological hazard repair programme" within the dam area was proceeding smoothly.
"Since the water level rose to 156 metres, there have not been any major geological disasters in the Three Gorges Dam area that have led to major loss of life or injuries."
The water level is expected to reach its maximum 175 metres next year.
The $22bn dam is the world's biggest hydropower project and the answer to Beijing's century-old dream to harness the Yangtze, the world's third-largest river, for electricity generation and flood control.
The high cost and potentially massive environmental impact of the project which began in 1993 has drawn criticism.
The massive project has displaced about 1.4 million mostly poor farmers who have either been moved to higher ground from areas that will be flooded by the reservoir, or relocated to neighbouring provinces.