"They were probably doing about 70km/h and we just did our best to signal them and get past," Goodman told Fairfax.
"Obviously having kids in the car you just want to get out of there quickly."
He alerted the driver that the campervan was on the wrong side of the road and "they just calmly made their way back across the road as if nothing had happened".
Goodman was stunned by the driver's behaviour.
"There was pretty steady traffic, being a sunny Sunday afternoon, and we were just waiting for someone to come round the corner and hit them," he told Fairfax.
"I've never seen anything like it before."
Goodman believed foreign drivers should be forced to pass a basic road test before being allowed to drive a rental vehicle.
"I expect they've just come over, off the plane, and jumped straight in a campervan. They should at least be told a few road rules before they're allowed to get going."
Tourism Holdings Ltd, which rented the filmed campervan, said the driver had been contacted and "reminded about safe driving in New Zealand, especially staying left," Fairfax reported.