Police can advise the Port to Southern Link, at Grafton, has reopened for southbound traffic.

Police acknowledge motorists' cooperation following the incident earlier this afternoon.

Police are advising the Port link to the Southern Motorway, at Grafton, is currently closed.

A pedestrian has been critically injured, and diversions have been put in place in the area.

The northbound lane of the Christchurch Northern Motorway, on Waimakariri Bridge, is blocked following a mud spill this afternoon.

Police were called to the spill around 3.40pm.