The sites have been constructed without approval from local authorities, to offer accommodation, camping and stand-up paddle board services to tourists at the lake, 75 km from HCMC.
Local authorities said they had previously ordered owners of the illegally-built sites to dismantle their facilities but they failed to comply.
Over 30 illegal sites have been built on agricultural land and floodplain areas around the lake in Dong Nai’s Vinh Cuu District, creating pollution, authorities said.
Covering 32,000 hectares, Tri An is responsible for storing water to supply the Tri An hydropower plant.
Dau Tieng and Tri An Lakes are the two main sources of fresh water for more than 10 million people in Vietnam's southern metropolis of HCMC.