Canterbury Police believe the three people injured in Ashburton on Sunday were involved in an altercation.
Officers found two seriously injured people in a car on William Street about 2 a.m. Sunday after following another lane on the same street.
Both were taken to hospital by the police. A third person was also seriously injured, but was taken to hospital.
Police said it appears the three people knew each other and no one else was wanted. in connection with the argument.
Officers are still trying to determine what happened.
Anyone with information about the incident should call 105 quoting file number 240526/1036 or report it anonymously via Crimestoppers – 0800 555 111.
With RNZ