There are hopes the Ashburton Bridge will open for all traffic later on Thursday.
The major State Highway 1 link was shut to all vehicles on Tuesday after drivers reported a slump in the bridge road.
The bridge has been open again for light vehicles but not trucks.
The intense rain earlier this week across Canterbury caused havoc, with roads washing out and farms flooded.
Canterbury emergency response manager Janelle Mackie spoke to Susie Ferguson.
