Engineers trying to clear a truck crash in the Wairau Valley may be the cause behind banking and EFTPOS outages across Marlborough.
The truck driver was moderately injured after hitting the Wye River Bridge, 50km north of Renwick, at 5:45am on Sunday.
Police say engineers were trying to fix the bridge, which is completely blocked off, when they cut through a fibre-optic cable.
The crash cut off the main alternative road to Picton, which was established after the Kaikoura earthquake cut off State Highway 1.
The only way through now is via a ford bypass, which police say will only be passable if weather conditions are favourable.
Motorists are asked to avoid State Highway 63, and the bridge is expected to be closed for most of the day.