A Waka Kotahi manager says major storms are beginning to happen too often for road authorities to keep up in parts of Tasman-Marlborough.
Speaking to 1News, the agency's top of the south systems manager Andrew James said the agency was bracing for more damage on state highways.
"We are expecting more slips to come down over the next days or weeks," he said.
James said the agency was struggling to keep up with the frequency of weather events after floods last July. He said crews were still working to fix damage from last year's rainstorm.
"We just can't get on top of it [in the Marlborough Sounds], and this is probably a situation across the whole of the network," he said.
Last July, storms damaged over 400km of roads in the region with an estimated $85 million repair bill.
Prior to this month's storm, Marlborough's deputy mayor told 1News that it would be one of the largest local roading repair jobs in the country's history.
James said the latest flooding would likely have to bring about changes in the agency's strategy for the region.
"We're not having the time to recover and then we're getting another event - and Nelson might find that now we're just getting event after event after event.
"We can't get the road stabilised before we get another event, and it means we're going to have to review the strategy in the Sounds."
As compared to the year before, James said he expected damage to roads in some parts of the region, like Whangamoa, to be worse this time around.
"We still don't really understand the full extent of the damage up there," he said. "We're getting quite used to these things but the costs of these recoveries is becoming really a concern."
More damaging and more frequent thunderstorms are expected in the coming years and decades as New Zealand faces the effects of climate change.
Scientists say storms, droughts, heatwaves, and wildfires will get progressively worse as a result of the toll of a warming climate.
Data shows parts of the Tasman-Marlborough region are among the most vulnerable to sea level rise in coming decades.