"I was tooting and tooting at him a good five to six times and he didn't take any notice," she said.
"He only got back on to the right side after swerving to avoid an oncoming car."
Mrs Hansen said she waited until the Jucy Rentals van pulled over before she stopped behind and approached the driver.
She said the driver was an "older male with a thick European accent" and to her knowledge was the only occupant of the vehicle.
"He had no idea what had just happened.
"I asked him if he knew what he had done and he sort of just said, 'Thank you,' and I said, 'You could have just killed a Kiwi, what are you doing?'"
Mrs Hansen said the driver then tried to extend a handshake to her, which she rejected.
She alerted a couple walking past but was upset they did not help her.
She then called police.
Mrs Hansen said she had just read an article that very morning in The New Zealand Herald about how a tourist driver was sentenced to jail after killing a child and injuring others in a collision in the South Island.
Senior Sergeant Phil Gillbanks said police were aware of the incident but were unable to attend. They had since followed it up.
AA motoring affairs general manager Mike Noon, said a lot of driving incidents involving foreign drivers arose after they had left a rest area or an intersection.
"It then becomes more difficult to correct or realise when there's not a lot of traffic to guide you, and that is why roads with less traffic are more difficult for those drivers.
"When there is a lot of traffic it's then much easier because you can see because there are other cars," said Mr Noon.
He said that, in this case, the driver probably did not exit on to the wrong side of the road deliberately but rather may have had a "momentarily lapse".
The AA has called for a project successfully carried out in the South Island to be brought to heavy tourism areas throughout the country.
The project included rumble strips being on both left and centre road lines, more direction arrows printed on roads and metal fencing ropes in heavy traffic areas.
Head of Jucy Rental Marketing Zoe Macfarlane said she was concerned to hear someone had allegedly been driving one of their vehicles in a manner "which is less than safe."
"However, we have yet to confirm that this is in fact the case.
"It is also difficult for us to confirm as to whether this vehicle was driven by a tourist driver as a great many of our cars are leased to New Zealand domestic drivers also" Ms Macfarlane said in a statement.
"In terms of our rental policies we have a robust system in place for all drivers that we hire to."
Ms Macfarlane said their policy included asking customers to watch a driver safety video in the branch before departing, if the branch staff assess that they were unfamiliar with driving on New Zealand roads or uncomfortable driving a rental vehicle.
Ms Macfarlane said Jucy Rentals worked closely with the Rental Vehicle Association and New Zealand Transport Agency and were involved in the development of a new Drive Safe website.
"We take driver safety seriously and have a manner of steps in place to improve driver education and reduce incidents."
