SH1 was closed near the intersection with Chertsey Line Road following a crash. Photo: Google

Motorists heading home for the day are being warned to expect delays after a crash left two people injured — one critically — and closed a section of State Highway 1 south of Christchurch.

A police spokesperson said the Rakaia Highway (SH1) was closed near the intersection with Chertsey Line Rd following the crash at 3.10pm on Thursday.

One person has been critically injured and another has minor injuries after the two-vehicle crash.

The spokesperson said the train tracks on SH1 were also blocked and police had notified KiwiRail.

Diversions are in place at Wilkinson Rd and Hatfield-Overdale Rd.

“Motorists are advised to avoid the area and expect ongoing delays,” the spokesperson said.