Prime Minister John Key says it is hard to see how quake-damaged Kaikoura's coastal State Highway One can be salvaged.
It's "really stuffed", Key said.
Key, in his second visit to Kaikoura since Monday's quake, and Transport Minister Simon Bridges flew over the devastated region in an RNZAF NH90 helicopter.
It was Bridges' first look at the slips and damage to the coastal State Highway One and the rail line.
Bridges' verdict when he saw the first major slip was "pretty messy".
But Key pointed out that it was not the biggest one "by any stretch of the imagination", pointing out massive slips that had totally obliterated the road.
"This road is really stuffed and there's thousands of metres of it. I just don't see how you can ever repair that bit of road. The whole mountain has moved over."
He said on his earlier visit on Monday they had seen the northernmost damage.
"We thought thought 'that's not too bad.' Then we got to here."
As they flew over a train marooned between two slips, Key observed the train and driver had been saved by lucky timing.
"Being in the tunnel probably saved him."
Key said one slip alone would have taken the road out for while and cost a lot to fix.
NZTA regional performance manager Mark Owen said one of the issues was bringing the slip down in a controlled manner, as well as having to work in a marine environment.
He was expecting satellite imagery today to allow them to assess exactly how many slips there were.
Owen said there was also major bridge damage "much worse than after the Christchurch earthquakes" on SH 70. A ford would have to be put in place at one point to get the road open again.
Kaikoura MP Stuart Smith had arranged for local farmers and businesses to meet Key.
Smith said water supplies were still a problem and farmers were concerned about diesel.
He said tourism companies such as Whale Watch were concerned because the lifting of the seabed in the earthquake had affected their ability to operate.
Meanwhile, a long line of helicopters waited in Kaikoura, part of the effort to bring in supplies and take out stranded visitors.
Naval vessels from the US, Australia, Canada and Japan were also diverting from celebrations for the Royal NZ Navy's 75th anniversary in Auckland to provide support in Kaikoura.