Three companies have been named to carry out crucial re-surveying work in quake-hit Canterbury.
Land Information New Zealand says the 7.1 magnitude earthquake on 4 September moved large parts of Canterbury by between 10 centimetres and a metre.
Spokesperson Graeme Blick says the flood plains have shifted, so precise levels are needed to ensure hazard monitoring doesn't suffer.
Mr Blick says work on this scale was last done after the 1987 Edgecumbe earthquake.
Canterbury has about 400 survey markers which now need to be rejigged.
The re-mapping will be carried out by the companies Opus, Beca, and CPG and should be finished by the middle of the year.