"In Saturday's fatal crash the driver of the van was not wearing a seat belt and was thrown from the vehicle when it collided with a south-bound car on Durham St."
The driver died at the scene and two occupants of the car were in Christchurch Hospital in a critical condition.
"CCTV footage of the van prior to the crash shows it speeding the wrong way along Salisbury St," Mr Stewart said.
"Police want every journey to be a safe journey and urge road users to take simple steps before they get behind the wheel or on their bikes such as wearing seat belts, driving to the conditions, if you drink don't drive and don't drive tired."
If anyone witnessed either of the weekend's fatal crashes and haven't spoken to Police please call Christchurch Central Police station on 03 363 7400.
Information can also be provided anonymously by calling Crimestoppers on 0800 555 111.