Her male companion, who was in the van's front passenger seat, was uninjured.
Police diverted southbound traffic at Waipu, directing vehicles off SH1 to Kaiwaka, via Mangawhai. Northbound SH1 traffic was diverted past the Brynderwyn hill via Maungaturoto and the Waipu Gorge road until about 2.30pm.
Cafe owner Maggie Everett said the couple had called in to the cafe to have a bite to eat.
When they left the cafe carpark, the shop's security cameras showed the van manoeuvring around a milk truck before turning to go south.
"The truck driver was putting his foot down - as they all do - to get up the hill," she said.
The crash took place in front of the cafe and the impact carried the van, pinned to the front of the truck, up the hill to the front of a building which was once a service station.
Constable Lleu Smart of Maungaturoto and Whangarei police serious crash unit Senior Constable Warren Bunn both told the Advocate the Swiss woman was fortunate her injuries had not been more severe.