Christchurch firefighters were told to "stand down" by Rural Fire officials and return to their stations on the first day fires started to engulf the Port Hills, the NZ Professional Firefighters Union says.
The union, which represents all career front line firefighters, said officials gave the order at nightfall on day one, "leaving career firefighters frustrated, bewildered and disappointed".
"The fire was left to burn out of control and the frustrated firefighters could see the flames from their stations," Secretary Derek Best told 1 NEWS.
It wasn't until 90 minutes later the alarm was raised to respond.
"As a result of returning to the locality from which they had been stood down from, they saved at least six houses from total destruction," said the union.
About 450 homes have been evacuated since the fires started burning on Monday, with eleven destroyed.
As a result of the stand down, the union says it is starting to question whether more houses could have been saved.
"The union and firefighters seriously question the tactical command decisions made and believes the tactics adopted were significantly flawed," Mr Best said.
The union says there is an urgent need for a full and independent inquiry.
Comment has been sought from Selwyn District Rural Fire officials this afternoon.
Christchurch Mayor Lianne Dalziel has been criticised for not issuing a formal Civil Defence state of emergency early enough, but she says it would have "made no difference to the people on the ground doing the work".
Civil Defence Minister Gerry Brownlee, however, has said that the state of emergency should indeed have been put in place earlier.
"It was a fire that raged for, in an increasing intensity for two and a half days before that was even on the table as a consideration," he said, adding that the decision will be reviewed.