Early indications also suggested the driver of the truck was not at fault, Mr Strieker said.
"The information received at this point suggests that the truck driver was driving appropriately. Serious crash which attended the scene, will give a detailed analysis but the findings will be some way off.
"Police are methodically working through a number of key witnesses - drivers who witnessed the crash and witnessed the events before and after the crash."
Canterbury West Coast Air Rescue spokesman Simon Duncan said one of its helicopters attended the accident.
"It was quite a horrific crash," he said. "The female passenger was ejected from the vehicle on impact and was confirmed dead at the scene."
Paramedics from the helicopter attempted to save the man, who had stayed in the car. "They tried to secure his airways, but unfortunately he passed away."
Mr Strieker said the driver of the truck was uninjured in the crash, however, he was "very distressed and upset".
"It is an extremely traumatic process to go through and police have provided the appropriate agency support to him and he is strongly supported by the management team at his firm, and his family."
He said he believed police had spoken to the family of the deceased and the the victims may have been related.
"Clearly they are known to each other but at this stage it is not known in what capacity.
"Our thoughts are with the victims of this crash and their families. It is an extremely traumatic thing to go through and it is tough times ahead for them."
He went on to urge motorists to "consider other motorists" while driving on state highways.
"Also consider your speed, drive to the conditions and keep safe distances when travelling behind vehicles. It is just a terrible thing to happen and it is an awful crash which, on appearances, appears to have been avoidable."
Investigations into the crash by the Police Special Investigations Unit are ongoing.
