Paramedics from Western Australia had been travelling through the region at the time.
They were first on the scene and commenced first-aid before emergency services arrived, Mr Mould said.
The killed tourist was lying outside the vehicle when firefighters arrived. Two other people, one in each of the vehicles, had to be freed with specialist equipment, he said.
"It was particularly nasty, it was as bad as it gets with three [people] seriously injured and one deceased."
The road was one of the main highways on the scenic route inland from Christchurch to Tekapo and Queenstown and was popular with tourists, he said.
Due to the severity of the crash it was difficult to determine which directions the two cars had been travelling in, Mr Mould said.
The two surviving tourists - a male and female - were airlifted by helicopter to Christchurch Hospital with serious injuries, police said.
Another man was taken to Timaru Hospital by road in a moderate condition.
Overseas drivers were involved in at least 558 crashes that resulted in death or injury last year.
In about three-quarters of the cases, the visitors were found at fault, including 11 crashes that were fatal.
Police estimate overseas drivers are involved in 25 per cent of South Island crashes, compared with 2 per cent nationwide.
In April, Queenstown's top police officer Senior Sergeant John Fookes said police should be able to ban unskilled drivers and seize their licences.
He said police in areas such as Queenstown had noticed a rise in accidents caused by tourists not used to New Zealand conditions.
He was speaking at the inquest into the death of motorcyclists Grant John Roberts and Dennis Michael Pederson, killed in 2012 when they collided with a rental car driven by Chinese national Kejia Zheng on State Highway 8 near Tarras.
Fatal crashes caused by foreign drivers
• Dutchman Johannes Jacobus Appelman, 52, pleaded guilty in the Christchurch District Court in June to a triple fatality collision after running a stop sign in Rakaia in a rental vehicle at Queen's Birthday weekend.
• The night before the fatal collision, US tourist Cody Dickey crossed the centreline in his campervan on the Coromandel Peninsula, killing Aucklander Robyn Eilleen Derrick, a passenger in an oncoming four-wheel-drive.
• On February 11, French tourist Gilles Georges Jego, 59, killed a female pillion motorcycle passenger in the Far North when he was driving on the wrong side of the road.
• An 18-year-old pregnant woman was seriously injured and lost her unborn child in Whangarei on February 9 after 27-year-old French tourist Marion Laure Heurteboust drove on the wrong side of the road.
• Canadian tourist Uri Tak Kau Law, 59, drowned on February 4 after crashing over the side of a Southland bridge. Nine others in the van survived.
