Supermarkets south of Ashburton in the South Island are dealing with a serious logistics challenge after road and rail links were cut by floodwaters south of Ashburton. 

Both Foodstuffs and Countdown have confirmed that deliveries to stores south of Christchurch are being impacted by the flooding, with many detours currently impassable. 

Supermarket supplies, freight and mail to South Canterbury, Otago and Southland are all affected with only air links working.

In Ashburton, the town’s bridge across the heavily flooded Rakaia River is currently impassable, visibly slumping in the centre. As waters began to recede late yesterday, engineers were beginning to assess the seriousness of the damage, lowering 12 14-tonne concrete blocks by crane at intervals across the structure to determine the strength of supporting piers, the foundations of which have been eroded by floodwaters. 

But John Tookey, a professor of construction at Auckland University of Technology, told Stuff that any hopes to keep a degree of traffic flow across the structure ahead of repairs being completed was “wishful thinking”.

Other bridges suitable for use as a bypass are also closed due to widespread flooding across the region, leaving Ashburton isolated from the rest of the country. 

”If you want to go south of Ashburton in a truck it’s about a 13-hour deviation to go via Lewis Pass and down through the West Coast,” New Zealand Trucking Association CEO David Boyce​ told One News. 

Washouts have affected railway lines between Rolleston and Washdyke and there has been damage to some railway bridges on the Main South Line. 

While all Countdown and Foodstuffs stores remain open in the South Island, a Countdown spokesperson confirmed that deliveries have been impacted to Timaru, Dunedin, Mosgiel, Oamaru, Gore, Invercargill and Queenstown.

“There will be some gaps on shelves but we’re closely watching the roads and we’ll get deliveries underway as soon as we can,” they said. 

“We’re working with our suppliers, transport partners and our stores to help minimise any impact to customers but certainly there are some challenges out there today.”

Hundreds of people have been evacuated in the South Island after relentless rain and people have been rescued by Royal New Zealand Air Force helicopters. Rural roads have been closed, bridges washed out and farms inundated since the weekend.