Two people have died following a serious crash between a car and a truck this morning on Main South Rd.
The truck driver has been taken to hospital with moderate injuries.
The crash has closed part of SH1, south of Rolleston near Dunns Crossing Rd, and the highway is expected to remain closed until mid-afternoon, police said.
Police and emergency services were called to the crash site at 10.10am.
"The highway is blocked between Dunns Crossing Rd and Burnham Rd," police said in a statement.
"Diversions are being put in place. Motorists are asked to avoid the area."
Steven Mann, senior travel information advisor Christchurch Transport Operations Centre, said there were considerable delays in the area.
"Motorists are asked to avoid this route in the meantime and to obey the directions of emergency services."
The crash had closed SH1 south of Rolleston near Burnham and Dunns Crossing Rd.
Mann advised motorists to avoid this route or delay their journey and a detour route has been set up for passenger vehicles and for heavy trucks.
The deaths bring the fatalities total this year so far to 355, three more than over the same period last year.