After a two-and-a-half hour delay at Lyford, the convoy continued.
Large landslides at various places made progress slow, as road contractors work with heavy machinery to clear the way.
A 25km stretch north of Lyford is the worst hit, with slips, gouged roads and rockfall.
Giant boulders are littered on both sides of the road at some points.
The fourth supply mission is carrying portable toilets, hospital supplies, huge generators, 8000-litres of petrol, 12,000-litres of diesel, gas bottles, and fresh food, milk and water.
The Inland Rd to Kaikoura is closed to all traffic except the military.
Large landslides caused by last Monday's giant magnitude-7.8 tremor took out the road at several places. The violent shaking also tore open cracks and crevasses in the road.
The first army convoy got through to Kaikoura on Friday.
John Key visits residents
Meanwhile, John Key has handed out blue bubble toys made by Hanmer Springs children to students at Waiau School today.
About seven of the 55 year one - year six students had their homes red-stickered, said Principal Mary Kimber.
It was like Santa had come early for many of the kids as they gladly accepted the toys.
They were impressed with Key's entrance, as his military NH90 helicopter kicked up a storm of freshly cut grass as it landed.
Several of the children told Key how they were living in camper vans or other houses after the quake. Most of the kids live on sheep or beef farms in the rural area.
One child said there were lots of cracks in her house. Another said their dairy shed had come off its wheels. Someone else said there was a big slip in their backyard.
