State Highway 1 at Waikuku in North Canterbury is closed tonight following a serious crash.

An NZTA spokesperson said the crash occurred on SH1 near the intersection with Waikuku Beach Road.

Chris Lynch Media understands at least 2 vehicles were involved and multiple people were injured.

Road users should follow the directions of emergency services at the scene and allow extra time for travel, the spokesperson said.

A detour is in place, with SH1 Main North Road closed between Tulls Road and Gressons Road while emergency services respond.

Southbound traffic should turn right onto Tulls Road, continue onto Smarts Road, turn left onto Rangiora Woodend Road, then left onto Gressons Road before rejoining SH1.

The reverse applies for northbound traffic, the spokesperson said.