China has declared a 60-kilometre section of Mekong River off-limits to all types of boats indefinitely while rock blasting is undertaken to widen the channel for commercial shipping operations.
China announced on Friday that operators of all types of boats should avoid entering the river from Guan Lei to Ganlanpa in Yunnan's Xishuangbanna prefecture.
It also also erected wires across the river to prevent boats from entering the section, which has now been declared a danger zone.
Guan Lei port, however, remains open to cargo and passenger boats as usual.
As a result of the river closure, passengers travelling by boat from Chiang Rai to Jinghong in China are now being transferred to a bus to travel on to their destination, about 100 kilometres earlier than they would have previously changed, said Pakaimas Vierra, vice-president of the Chiang Rai Chamber of Commerce yesterday.
Jinghong is the main city of Xishuangbanna and is popular among Thai tourists.
Ms Pakaimas insisted the closure of the river in China would not have any serious impact on tourism or cargo transport because travelling on to China by car is now convenient.
In 2000, China's plan to widen the Mekong River by blasting rocks to make it possible for a 300-tonne ship to navigate the stretch between Yunnan and Luang Prabang encountered resistance by Thai environmentalists over the possible impact on the river's ecosystem.
The resistance led China to move the rock-blasting further back to areas of the river situated within its territorial boundaries.