In a display of holiday spirit, or perhaps holiday traffic frustration, stranded motorists have helped emergency services clear a flipped van from one of Wellington's busiest tunnels.

Amateur video of the scene showed a large hole in the side of the tunnel, and a group of people trying to upright a white van.

The Terrace Tunnel, on State Highway 1 in Wellington, reopened after roughly an hour of closure earlier this afternoon, but not before it created widespread gridlock in the central city as commuters attempted to find alternative routes.

ROSS GIBLIN/FAIRFAX NZ There was a minor traffic build up but detours were in place, a police spokeswoman said.

A police spokeswoman said traffic was flowing steadily shortly after the van was towed away.

Police were notified of the crash at 11.15am.

The spokeswoman said the vehicle's occupants had only minor injuries.

REBECCA THOMSON/FAIRFAX NZ Police divert traffic away from the Terrace Tunnel in central Wellington.

There was a minor traffic build up but detours were in place, with traffic directed towards the earlier exit, she said.

A fire spokeswoman said no one was trapped in the vehicle when they arrived on the scene.

Police were not able to determine what caused the van to flip over.

New Zealand Transport Agency regional manager Mark Owens said the van caused superficial damage to the lining of the wall on the southbound side of the Terrace Tunnel.

"This will not affect the operation of the tunnel. The lining will be repaired during a routine night closure for maintenance early in 2017," he said.

Credit: Ash Moor (via Wellington - LIVE)

A two-vehicle crash on the Newlands on and off-ramp also blocked traffic for about an hour on Friday.

A police spokeswoman said they were called to the incident at 3.24pm.

One car was substantially damaged and debris was blocking the road.

No-one was injured in the crash.