The High Court in Christchurch has been told that red-zoning property is really the compulsory acquisition of the land - despite the Government's claim it is voluntary.
Sixty-eight owners of 45 properties are taking Earthquake Recovery Minister Gerry Brownlee and Canterbury Earthquake Recovery Authority chief executive Roger Sutton to court.
Most are only eligible for a buyout of 50% of the property value, as their land was vacant or uninsured following recent damaging earthquakes.
Their lawyer, Matthew Palmer, told the court on Monday that government documents showed it was necessary that the red zone be emptied for its recovery plans for the land.
Dr Palmer said the Government ensured it was an offer that could not be refused.
He quoted the letter outlining the buyout offer, saying if it was refused properties were likely to lose infrastructure services and the land might be acquired later at a reduced cost.
The plaintiffs, known as the Quake Outcasts, say the red zoning of property is unlawful and removed their property rights.
They want the red zoning to be declared illegal and for property owners to be offered either a buyout at 100% of the property value or to be allowed to remain on their property with ongoing services provided by councils.