A bomb scare that closed a downtown Wellington street followed a heated exchange between a bus driver and a male passenger, a witness says.

Police cordoned off a section of Willis St this evening over reports of threats made by someone on a bus.

Police said a 41-year-old man is in custody tonight and is due to appear in court tomorrow. He is charged in connection with outstanding warrants but further charges are likely.

Cordons were lifted about 7pm.

A Wellington commuter - who did not want to be named - said he was waiting at a bus stop on Willis St when he saw a driver pull over and kick a "big fella" off his bus.

"The bus driver was having a bit of a row with him but nothing major," the man said.

"Then the bus driver dragged off three big bags, overseas travel-sized bags."

The driver put the bags down and told the passenger to wait there until police arrived.

"It was all mellow, everyone was staying on the bus, they didn't seem that bothered," the witness said.

As the delay dragged on, the bus driver and the passenger got into a louder confrontation and began yelling at each other.

The other passengers then began to gradually get off the bus because they sensed it wasn't going to move anytime soon.

However, at no time, was there any panic or mention of a bomb, the commuter said.

It wasn't until police arrived 15 minutes later that the commuter heard the driver first mention the passenger had threatened him with a bomb in his bag.

"That's when everyone cleared out real quick and that's about 15 minutes after the bags had been put down on the sidewalk," the commuter said.

Police quickly responded with five cars arriving at the scene.

The commuter said he found it "weird" that he didn't hear the driver talk about a bomb or see any sign of panic among other passengers until police arrived.

Police said they were "not looking for anyone else in relation to the matter".

The incident occurred about 5.20pm and led to several buildings being evacuated along lower Willis St, according to Herald reporter Jason Walls.

Police officers had been going from business to business, instructing people to evacuate and get off Willis St.

Fellow reporter Devon Bolger said at the time she could see about 200 evacuated workers gathered on the street.

Police want to hear from anyone who was on the bus at the time of the incident who they have not already spoken to. They are asked to contact Wellington Police at [email protected].

"Any reported threats are taken extremely seriously by Police and the public
are thanked for their co-operation as the matter was resolved."