"This, like other areas we've zoned red, would have meant residents would have been forced off their land for a period of years.
"There were also no guarantees that the remediation solutions available, regardless of cost, would have worked."
The houses zoned red today were among the 10,500 left in limbo after a June 23 Government decision on the fate of quake-hit properties.
More than 5000 Christchurch homeowners have already been told their homes are red zoned and will not be repaired.
Owners of the houses zoned red today would receive offers from the Government to buy their property at its rateable value, Mr Brownlee said.
They would be eligible for the same support as residents whose homes were zoned red on June 23, he said.
"Today's news will be difficult for many people who've bravely hung on for nearly a year in the hope their property could be built on.
"While the news will disappoint some it also provides a clear, and we believe fair path ahead for the hardest hit residents of the Waimakariri District."
A decision on 70 more orange zoned properties should be made within the next few weeks, Mr Brownlee said.
CERA chief executive Roger Sutton commended Waimakariri orange-zone residents for their resilience in a letter sent in July.
"I know this has been a long process since September 4 with many subsequent aftershocks. I have been greatly impressed by the resilience the people of the Waimakariri have shown.
"Please be assured CERA and the Waimakariri District Council have been working as hard and fast as we can to achieve some certainty for you and to progress the recovery."
All earthquake-hit Canterbury areas have been zoned either red, orange, green or white.
Red zoning means the land isn't fit to keep living on, and the homeowner must decide whether to sell their land and home to the Government, or deal with their insurer.
Green means the homeowners can stay and get on with repairing or rebuilding damaged
homes.
