A mighty bang and the rattling of steel pipes alerted neighbours to the latest mishap on a building site where one man has already died.

A worker was taken to hospital with leg injuries and suspected broken ribs after an 8m concrete beam toppled over at the central Auckland site.

At the same site in January, Te Rue Teparia John Tearetoa was killed by a collapsing wall.

Occupational Safety and Health (OSH) closed part of the Parliament St site yesterday and was investigating.

Two men and a woman who were home watching America's Cup challenger races said they heard the bang about 2.45pm.

They rushed to their windows to see a man entangled in beams and steel pipes.

He was 2m off the ground, "pinned and wriggling", one said.

Construction workers ran to help the man.

The partially built apartment complex was soon surrounded by police, fire, ambulance and media vehicles.

Senior Sergeant Ross Endicott-Davies said the worker was taken to Auckland Hospital with moderate injuries, including bruising and grazes on his legs.

He was able to walk when freed from the pipes and beam.

The site is being developed by 1988 Olympic kayaker Brent Clode, whose firms Raiser Developments and Clode Consulting face 85 health, safety and building law charges in relation to the wall collapse.

After the death, Mr Clode employed Multiplex Constructions NZ to take over building the apartments.

Managing director Shane Brealey said that yesterday a beam fell when scaffolding gave way.

The worker, who was trapped between the beam and scaffolding, had a lucky escape.

Mr Brealey rejected the suggestion that the site was jinxed. Multiplex Constructions had no involvement in Mr Tearetoa's death, he said.

"This is a big shock to us. It's the call you don't want to receive. You wake up in the morning and hope not to get that call."

Mr Brealey said OSH visited the site two weeks ago and considered it to be a "model project".

OSH spokeswoman Madeleine Setchell confirmed that the site looked good two weeks ago, but said construction sites changed daily.

For instance, no concrete beams were being installed during the earlier visit.

Miss Setchell said the area where the accident happened would stay shut until deemed safe.

Mr Endicott-Davies said a nearby crane did not seem to be involved in the accident.

"He was very, very lucky to have escaped more serious injury."

The Parliament St building will have 15 stories and 232 apartments when finished next September. There were about 10 managers and 40 to 50 subcontractors working on-site during yesterday's accident.

Mr Tearetoa, 39, of Mangere, was killed in the January accident and Leslie Bruce Harvey, of Glen Innes, was taken to Auckland Hospital with a broken leg.

Mr Tearetoa had been working for labour hire company Allied Workforce. Multiplex's Mr Brealey said new subcontractors were now working on the site.

The charges against Mr Clode's firms will be heard late next month.

Mr Clode could not be reached yesterday.