Married couple killed in double fatal Rakaia crash were Fox and Joan McCrossin of Victoria, Australia

Emergency services at the scene of the serious crash involving a truck and other vehicles on State Highway 1 on Sunday near Rakaia. Photo / Bridget Shimmin

Two women who were killed in a crash involving a truck and several other vehicles south of Christchurch over the weekend have been named.

They were Fox McCrossin, 58, and her wife, Joan McCrossin, 56, of Victoria, Australia, police said.

The crash occurred on State Highway 1 (Main South Rd) in Bankside, Selwyn on Sunday about 8.50am.

Police were initially called to reports of a truck rolling onto a train line.

The McCrossins were killed in the crash and seven others received a range of injuries, police said.

"Police offer our condolences to their family and friends."

Police have named the two women killed in Sunday's crash. Photo / Bridget Shimmin

An investigation into the circumstances of the crash is continuing.

Photos showed the truck - that had been pulling two trailers - having flipped and come to rest across railway tracks, shutting down the train line south of Christchurch.

A resident of a local farm said he heard a bang and went out to see what had happened. He could only see the truck - no cars were visible from his farm's boundary.

The crash happened right on the Main South Rd bend, he said.

Bridget Shimmin was on a southbound Intercity bus that arrived on the scene not long after the crash.

She said a car that was involved in the crash had ended up at least 100m down the road.

"[It] sounds like the truck clipped the car and spun out of control as a result. I think a couple of other cars closely missed the truck and had to swerve out the way."

The bus had waited at the scene while several paramedics who happened to be on board went to help, Shimmin said.

Once they reboarded the bus was redirected onto a gravel road that looped back to SH1 just before Rakaia.

St John was called at 8.45am, and five ambulances and a helicopter were sent to crash, a spokeswoman said.

Three fire appliances from Rakaia and Dunsandel were also in attendance.