A major highway in Central Otago has reopened after a crash amid fog in the district.

State Highway 8/Cromwell-Clyde Rd in Clyde had been shut to westbound traffic, between the intersections with Hazlett St and Sunderland St, the NZ Transport Agency advised just after 8am today. 

The lane for eastbound traffic remained open, as emergency services worked at the scene.

Police said there were no injuries reported.

Road users on social media warned of difficult conditions this morning, saying it was very foggy in the Clyde area and vehicles didn't have their lights on.