It's a race against the clock for South Canterbury authorities ahead of forecast bad weather.
The New Zealand Transport Agency said Rangitata Bridge on State Highway 1 will open late this afternoon. The exact time is yet to be confirmed.
Waka Kotahi NZ Transport Agency System Manager Pete Connors said floodwaters were coming under control with joint action from Environment Canterbury, KiwiRail and Transport Agency river engineering and roading crews.
Teams have been trying to repair stop banks near the Rangitata River Bridge. A bund upstream of the highway is set to be completed by tomorrow to redirect water away.
Chorus is also finishing essential repairs to its network.
There is a small amount of surface water left at the SH1/ SH79 Orari intersection, but the highway is increasingly dry to the north, Mr Connors said.
"People can expect to see work continuing to strengthen and rebuild bunds around the river and stopbanks right through to Christmas," he said.
After peaking at 2,200 cubic metres of water a second (cumecs) during the Saturday flood, the river has now dropped to 330 cumecs, still five times its average flow. Given the pounding taken by the river’s protection systems at the weekend, it remains vulnerable in any future flood events, Environment Canterbury warned.
The alternate detour route for most of today is still Inland Route 72, via Arundel, until State Highway 1 reopens. Speed restrictions are in place and delays are expected.