The driver of a Toyota Corolla which crashed, killing himself and a cyclist in Christchurch, wasn't wearing a seatbelt and was believed to have been drinking.
Police also believed speed was a factor in the crash.
Emergency services were called to Empire Rd in Kainga, near the Old Waimakariri bridge on the northern outskirts of Christchurch, at 3.33pm on Friday.
Mark Vincent Green from Shirley, Christchurch, 57, and Phillip Eden, 60, from Ohoka died when a Toyota Corolla collided with a Downer truck-and-trailer unit, causing its trailer to hit a cyclist, police said.
Mr Eden was a cyclist and Mr Green was the driver of a Corolla at the time of the crash.
Inspector Al Stewart told Fairfax the 57-year-old was speeding south when he lost control of his car and crashed into a northbound Downer ute towing a trailer.
The trailer detached and hit Mr Eden as he was cycling north, Fairfax reported.
Mr Green wasn't wearing a seatbelt and was thrown from his car.
Mr Stewart said the man may have been drinking before the crash, but it had not been confirmed yet.
"If alcohol is involved it's disappointing to again see the trifecta of poor driving behaviour where alcohol, speed and [lack of] seat belts has resulted in fatalities."
He said the man would likely have faced charges if he had survived.