Olley said the one person wearing a seatbelt was able to walk out of the crash while the other survivor remained in hospital.
A police spokeswoman said a member of the public rang emergency services about 2.20am after coming across the rolled car near the corner of Harts and Southbridge Sedgemere Roads.
"Three occupants, two males and a female, were dead at the scene and two others were transported to hospital, one with serious injuries.
"Next of kin are in the process of being advised."
The Serious Crash Unit is investigating.
The holiday road toll now stands at seven since Friday afternoon.
The 83-year-old woman who died after being hit by a car in Takapuna, Auckland, on Friday night has been named as Myung Wha Lim.
Lim's death was the first of the Christmas road toll period, following the crash on Taharoto Rd shortly before 7pm on Friday.
Clifford Irving, 66, from Lower Hutt, died following a collision between a motorcycle and a ute on State Highway 2 in south Wairarapa yesterday evening.
Sione Taumalolo, 11, and Talita Moimoi, 33, died when a bus crashed down a 100 metre bank in Gisborne on Christmas Eve.
The official holiday road period began at 4pm on Friday, December 23, and runs until 6am on Wednesday, January 4.
Last year's Christmas road toll was 12, from 244 reported injury crashes.