Police have confirmed two people are dead, following a serious two-vehicle crash south of Christchurch, on State Highway One near Ealing Road, about 1.40pm.

Police were told of the crash on Ealing Rd, near State Highway 1 in the Ashburton district, at 1.39pm and had now made their way to the scene, a spokeswoman said.

Now, police have confirmed that two people have died in the smash.

St John spokeswoman Chrissy Hamilton said they have stood down the rescue helicopter that was scrambled. She referred further Inquiries to police.

Motorists are asked to avoid the area if possible.

SH1 at the intersection of Ealing Rd, between Ashburton and Rangitata, is currently closed.

The Christchurch Transport Operations Centre (CTOC) says detours are in place. Northbound traffic is turning on to SH79 at Rangitata, and then Route 72 Geraldine Arundel Rd, before a right on to Hinds Arundel Rd, Dalamine St back on to SH1 at Hinds. It's the reverse route for southbound traffic and CTOC says the detour "is not suitable for HPMVs but is okay for 50Max traffic".

The police Serious Crash Unit will be attending.