Police at the scene of the crash in Manners St on Thursday afternoon.

A man in his 50s is in a critical condition at Wellington Hospital's intensive care unit after he was hit by a bus in Manners St.

He had serious head injuries and also suffered serious facial injures in the accident, about 2.20pm, Wellington Free Ambulance spokeswoman Di Livingston said.

A section of the central city street, between Willis and Victoria streets, was closed to traffic, which particularly affected buses, but was reopened about 4.30pm.

ROSS GIBLIN/STUFF A pedestrian suffered serious injuries in the incident.

Police said the pedestrian had suffered serious injuries and was in hospital.

READ MORE:

* Pedestrian hit by bus outside Wellington's Opera House

* Drunk man steps in front of bus in black spot on Manners Mall, Wellington

* Two-bus crash in central Wellington

Motorists and pedestrians have been asked to avoid the area.

Visibly upset witness Michaela Pritz was walking near the man and saw him behind a tree near the crossing. She then heard a bang, and saw him on the ground.

"I was in shock," she said.

Vinko Kerr-Harris, who was having lunch in Subway across the street, saw the man step out and then get hit by the bus.

"It was pretty nasty," he said.

The injured man is the latest in a string of pedestrians to have been hit by buses on the Manners St stretch since it was turned into a two-way bus system in November 2010.

The Manners Mall road changes cost $11 million and five months of disruptive work.

Within two days of the its grand opening, the Manners Mall stretch of road saw two people hit by buses. The first was a teenage boy who walked away unscathed.

The next day a woman was hit and taken to Wellington Hospital in a critical condition.

Another person was hit by a bus in the same area before Christmas that same year, prompting a meeting between Go Wellington and Wellington City Council officials in a bid to avoid a boycott of the new Manners St bus route.

By February 2011, six pedestrians had been hit by buses. The last was a woman, in her 20s, taken to Wellington Hospital with serious injuries.

In 2012 Wellington city councillor Leonie Gill called for the installation of pedestrian fences to stop people being hit by buses. However, the council was reluctant because it feared fences or barricades could trap jaywalkers on the road, and increase the likelihood of people being hit.

A woman suffered critical injuries in February 2014 when she walked across the road and was struck by the front of a bus. A witness saw the woman spin to the bus's rear before she landed head-first on the edge of the pavement.