The pier that supported a bridge along the expressway subsided by about half a meter, causing an estimated 50m of the road surface to sink in the middle. No injuries were reported.
The incident occurred on the Guangzhou to Shenzhen highway near to Dongguan.
Traffic police closed the Dongguan-Guangzhou section of the expressway, and diverted vehicles to the Beijing-Zhuhai expressway and state highway 107 connecting Beijing and Shenzhen.
The expressway opened in 1995 and the pier was reported to be undergoing maintenance when the subsidence occurred.
It was also reported that the expressway been subject to over four times the amount of daily traffic it was originally designed for and that there were complaints from highway operators that traffic authorities failed to enforce regulations on overloaded trucks.