The NZ Transport Agency (NZTA) has closed the Lyttelton Tunnel following today's major earthquake.
There are also reports of major damage to local roads in the city, as well as liquefaction and surface flooding.
The agency reports that the Rakaia Bridge on SH 1 south of Christchurch and the Waimakariri Bridge on SH1 north of Christchurch are both open.
NZTA staff have been evacuated from both of the agency’s premises in Christchurch. Further information on damage to the state highway network in the region will be provided as soon as it is available.
The NZTA advises motorists to limit travel to what is essential and to use extreme caution when driving until further notice.