"'Help us, help us'. This is all these poor kids were yelling out. 'Can you help us? Can you get us out? We want out, we're cold','' Amanda O'Donnell told One News.
"We told the kids to hang on: 'keep holding on, don't panic, we've got the chopper coming'.''
Another woman jumped into the water to help.
"We saw these kids yelling out for help so that's when I jumped in the water to help. I've got three kids myself so I understand,'' the woman said.
The brother of the man who owned the boat told One News the secondhand dinghy had only recently been purchased. He said the Mangere family were trying it out for the first time.
Senior Sergeant Ian Brenchley said the boat capsized about 2pm and the family were swept westward by the current.
Some of them managed to grab the pylons under the old Mangere bridge, which is next to the motorway bridge.
"Two members of the public have jumped into the water to assist them, so that was seven people in the water at one stage and we've recovered five of those. Police search and rescue are searching for the other two bodies,'' Mr Brenchley said.
St John Ambulance Counties-Manukau operations team manager Patsy Carlyle said a child was taken to Kidz First Children's Hospital in a critical condition and eight people, including the firefighter who also went into the water, were taken to Middlemore Hospital in moderate condition.
The child is believed to be aged three.
Station officer Willie McDonnell said the firefighter from Mangere suffered mild hypothermia when he swam out to rescue the people clinging to the old bridge.
"We let him out on a line because you can't really afford to let anyone go in that current - it was about half tide so it was getting pretty strong.''
The firefighter came back with two people, and another rescuer set about retrieving the others.
"He got a little bit chilly, I think he got mild hypothermia.''
Mr McDonnell said the situation was "flat out''.
"It was a little bit confused because people didn't know how many people were in the boat - I didn't even see a boat - all we found were the people clinging to the base of the bridge.''
The firefighter was treated then returned to the station.
He would be given the rest of the night off, Mr McDonnell said.
Mangere Boat Club Commodore Brian Anderson said he saw what looked like an overturned dinghy floating on the outgoing tide past the clubrooms, about 600m from the bridge.
It was a small vessel and did not look suitable to carry many people.
"Looking at it through the binoculars, that is very overloaded,'' he said.
Conditions had been fine this afternoon
By APNZ and NZ Herald staff
