The NZTA is assessing the impact of the Canterbury earthquake on the region's state highway network.
While initial inspections show that the region's highways appear to have held up well, NZTA Canterbury State Highways Operations Manager Peter Connors says it could be several weeks before the full extent of any damage is known.
"Our immediate priority is ensuring the safety of road users. While most state highways in the region are open, we are asking people to take extra care and be very cautious if they do need to drive."
Mr Connors said the major focus of the NZTA's work over the next few days would be ensuring that obvious damage to state highways in the region is repaired as quickly as possible.
"Contractors are already out flattening humps in the road caused by the quake and working on damage to some bridge abutments."
All state highways in and around Christchurch are usable. The major structures including the Lyttelton Tunnel have been assessed for structural integrity and given the all clear. Key bridges on State Highway 1 over the Ashburton and Rakaia Rivers to the south of Christchurch and across the Waimakariri River north of Christchurch are operational.
While the Chaney's Road on Ramp on to State Highway 1 north of Christchurch is closed, this doesn't affect motorway traffic other than that which uses the ramp. State Highway 77 between Methven and Windwhistle in Mid Canterbury is the only state highway currently closed due to earthquake damage. A large slip south of the Rakaia Gorge is currently being cleared and it is anticipated that this road will be open to single lane of traffic by nightfall.
The earthquake does not appear to have had any impact on state highways on the West Coast or the Otago and Southland regions.
Information on earthquake damage to state highways in Canterbury will be regularly updated on www.highwayinfo.govt.nz(external link) or is available by phoning 0800 44 44 49.