Parry said the person appeared to be searching for something in the car. Worried that it could be a weapon, the staff decided it was safest to retreat to the safe room and call the police.
A police media spokeswoman confirmed they received a report of a person allegedly behaving suspiciously at the restaurant at 11.01pm.
A person was taken into custody, she said.
Parry said he was pleased with the safety-first approach his staff took.
"They took a super cautious response and I would prefer that every time," he said.
"They made the right call and it's a call I'm thrilled they made."
He said the safe room was designed for armed robberies or any situation in which staff felt threatened.
"It originated from a spate of robberies in Auckland. Every site in the country has got it and it works well in this day in age."
A 51-year-old man was arrested and is expected to appear in Rotorua District Court tomorrow on two drug-related charges.