Motorists travelling the alternative route between Christchurch and Picton have been caught up in heavy congestion today, as traffic pressure mounts on the post-quake thoroughfare.
With landslides and quake damage closing SH1 around the Kaikoura area, the inland alternative route has been used by four times the usual amount of traffic, including more truck and trailer units.
Paul Mcdonald told Fairfax traffic had backed up as crews worked to repair a bridge between St Arnaud and Kawatiri, which had been closed for resealing.
"The road looks to have caved in because of the loads going over it," he said.
"On our side, at a guess there are at least 50 cars waiting."