Police say it could be some time before it is known what caused a mini-bus crash near Luggate on Friday, which killed a 62-year-old Indian woman.
Southern District Command Centre Senior Sergeant Brian Benn said the investigation was taking longer than usual because of the health of the surviving occupants and "the language barrier''.
Kusum Rohit Kenia, of Mumbai, died in the crash.
She was one of seven in the vehicle when it left the road and collided with a drainage bank on State Highway 6, 10km south of Luggate.
The remaining six occupants were transported to hospital by helicopter and ambulance.
Two have been discharged from hospital, but four remain in Dunedin Hospital in serious, but stable conditions.
"I would imagine it will be a little while before that [the cause of the accident] comes out,'' Snr Sgt Benn said.
"Some of the occupants of the vehicle haven't been interviewed yet because of their medical condition - they're still in hospital.
"And the other complication to that is the language barrier. We've got to get interpreters to do those interviews.
"It is slowing the process.''
Police serious crash investigators are continuing their investigation into the cause of the crash.
Because the investigation was still ongoing, Snr Sgt Benn said police were not in a position to comment on the likely cause of the crash.
However, he said there did not appear to be any obvious causes, such as a tyre blow-out.
It was not known when the crash investigator's report would be ready, he said.
