Armed police board passenger bus in Wellington

A commuter has described the moment armed police swooped on a central Wellington bus this morning in the hunt for a robber.

Andrew Lawler was on his way to work when he noticed police cars with lights and sirens beginning to surround the bus he was on.

He did not think much of it until one of the cars began signalling for the bus to pull over.

"At least six police officers got out with their guns pointing at the bus, I think at least one of them had an assault rifle.

"They were ready to go if something went down."

One of the officers got on the bus and told everyone to stay still, before doing a search of the vehicle.

"I could definitely remember seeing one lady at the back of the bus, her eyes just had that fear factor. She looked very scared, and you can understand why. When a police officer gets onto a bus with his gun out and there's not really anywhere to go, you can see why people would be scared in that situation."

Lawler thought other passengers were "in shock" during the incident.

He said it was "exciting" and "like an action movie".

Police were searching for a man following the attempted robbery of an individual on a street in Berhampore. Shortly after 7am police received information he may have been on the bus.

"Initial information suggested the robbery may have involved a weapon, and armed police were deployed as a result," police said in a statement.

"Police spoke to a specific individual on the bus and established they were not the person being sought."

Staff took time to explain to the passengers and the driver why the bus had been stopped, and they able to continue their journey shortly after.

"Inquiries into the incident are continuing. It has not been confirmed if a weapon was involved. Anyone who was on the bus who would like to speak with someone further can contact police to be put in touch with Victim Support."

A spokesman for Tranzurban confirmed it was one of their buses that was stopped.

Passengers on the No. 1 route bus were "fine" and "the driver did a great job", he said.

"An exciting start to the day for our passengers, and it's somewhat amusing to think a robber might use a public bus as a getaway vehicle."