More Christchurch properties red zoned

Earthquake Recovery Minister Gerry Brownlee said the decision was not easy given the size of the town and the patience shown by residents since September.

"Many options have been exhaustively considered; however, in full evaluation of the facts today's decision was clear cut."

He said the government had taken a "huge amount" of geotechnical engineering advice before deciding to red zone the additional properties.

"One inescapable fact was that the land and critical infrastructure beneath the hardest hit parts of Kaiapoi and Pines Beach was so badly damaged that any remediation solution would have required the complete removal of all homes we're zoning red today," Brownlee said.