A worker became stuck under the old Panmure Bridge when scaffolding collapsed into water this morning.
The collapse happened shortly before 10am on Lagoon Drive, East Auckland, injuring four.
The Fire Service said six people fell into the water and one was trapped, all of whom were working as scaffolders.
A Herald reporter could see a man wedged between the bridge and a concrete pillar, scaffolding debris strewn below him in the water and on the bank.
A fire engine moved underneath the bridge and extended a ladder to the trapped man.
Fire crews brought him to the top of the fire engine and safely to the ground.
He was able to walk and appeared uninjured.
Two people suffered moderate injuries and one had minor injuries. All three were taken to Middlemore Hospital. A fourth person was assessed at a medical clinc.
St Johns territorial manager for East Auckland Mark Deoki said bystanders helped the injured workers.
He said it was lucky the men were not closer to the centre of the bridge, where the entire scaffolding is now in the water.
Several workers at the scene were wearing uniforms with "Affordable Scaffholding" emblazoned across the back.
When the Herald approached Affordable Scaffholding, a spokesman for the company said he had no comment on the incident.
Earlier, two police cars and two fire engines were at the entrance to the bridge. Two ambulances were seen leaving the scene.
Police officers were directing traffic, which is now free-flowing.