Lambton Quay has reopened after a bomb disposal robot exploded a suspicious package left outside McDonald's.

Police say it will be some time before they can release any details of Wednesday's scare, which caused officers to cordon off a large part of the central city street, and to evacuate neighbouring buildings.

By evening, police lifted the cordon to traffic and pedestrians, and officers left the scene, where they appeared to have been collecting fragments of the package, and taking photos.

1 of 6 ROBERT KITCHIN/FAIRFAX NZ A police robot dealing with a suspicious package on Lambton Quay. 2 of 6 ROBERT KITCHIN/ FAIRFAX NZ A police officer confirmed a suspicious package was found in the Wellington CBD. A bomb disposal robot is used to approach the package. 3 of 6 TOMMY LIVINGSTON/FAIRFAX NZ Police have cordoned off large parts of Lambton Quay and surrounding streets. 4 of 6 SIMOE TALEPITA Several office buildings around McDonald's were evacuated. 5 of 6 The police bomb squad on Lambton Quay 6 of 6 TOMMY LIVINGSTON/FAIRFAX NZ One man who was evacuated said his office was told to leave their work stations immediately and exit the building. Police asked people to stand on the street.

Police were called about 2.30pm, and set up a cordon that stretched from the Willis St end of Lambton Quay to the Brandon St intersection.

Occupants of buildings inside the cordon were told to go home soon after 3pm, although many waited near the scene hoping to retrieve belongings from the buildings.

Police would confirm only that a suspicious package had been found, and a Defence Force robot was brought in. The investigation was continuing, a statement issued about 7pm said.

A bystander's photo of the suspicious package.

"When the NZDF team and police were satisfied that the item posed no risk to the safety of the public or their staff, the cordons were lifted."

Before the explosion, an announcement on a police loudspeaker asked that "everyone on Lambton Quay please stand on the road", and police warned people to stand away from windows.

The crowd was moved off the street, away from windows and glass, and many huddled in the middle of the road.

One man from an evacuated building said everyone in his office had been told to leave their work stations immediately, and get out.

Another person, who did not want to be named, said everyone had left the office and been sent home.

A man who was in Hannahs shoe shop at the time said police told everyone to leave.

"They just came in and told everyone to get out. They said there was a bomb threat."

A woman who had been in a building close to where the package was found said she had no idea what was going on.

"We didn't know what to think. If I knew it was this serious, I would have grabbed my stuff.

"We asked the police what was going on, and they wouldn't say."

Buses were diverted around the cordon, with no stops being made at ANZ, the Cable Car or Kirkcaldie & Stains.