"While we try to stick to our timetable, we're incredibly conscious of safety to our passengers and follow all guidelines from NZTA regarding road closures," said spokeswoman Sheryll Otway in a statement.
"At the point of starting the journey from Auckland at 2130, the road was open and NZTA had not issued a road-closure warning.
"Our passengers are being well looked after by the army who are providing accommodation and meals."
Otway said Mana Bus were monitoring the situation and would be updating its passengers on travel when NZTA confirmed the roads were open and safe to travel on.
"If any of our customers wish to avoid travel in the next 24 hours due to the weather forecast, we're more than happy to rebook or refund their travel.
"The passengers had spent part of the day holed up in the Oasis Hotel bar, but have since been moved to the army barracks.
