Nine people have died and 70 were hospitalised after strong winds caused boats carrying tourists to capsize at a scenic spot in southwestern China.

The passenger boats overturned on Sunday afternoon on a river in Qianxi city, Guizhou province, state broadcaster CCTV said, sending 84 people into waters.

As of Monday morning nine were dead, 70 have been hospitalised and four were unharmed, state media said. One remains missing.

President Xi Jinping urged "all-out efforts" in the search and rescue operations and treatment of those injured, Xinhua news agency said.

Xi also "underscored the importance of strengthening safety measures in tourist attractions" and other large public venues.

Vice Premier Zhang Guoqing was dispatched to the scene to oversee the rescue efforts, state media added.

An investigation has found the boats were not overloaded with passengers, CCTV said. (AFP)