Thai AirAsia is facing heavy penalties from China's civil aviation regulator for illegally changing flight plan without permission.

The Civil Aviation Administration of China (CAAC) previously approved the low-cost carrier to operate 10 charter flights between Hohhot, Inner Mongolia and Pattaya, Thailand in January and February 2017.

However, it is found Thai AirAsia adjusted the flight plan without getting permission from the regulator, the Chinese aviation watchdog said in a statement on January 22.

The CAAC added that this was in clear violation of Chinese civil aviation regulations and endangered aviation safety.

As a punishment, Thai AirAsia was stopped operating the Hohhot-Pattaya route and is now under further investigation.