The largest army aid convoy to resupply earthquake-stricken Kaikoura through the treacherous emergency inland route has resumed after it was delayed by weather.

A total of 32 NZDF trucks carrying essential supplies set off from Culverden rugby fields at 6.30am.

Deteriorating conditions prevented an aerial check of the damaged road and the convoy was halted at Mt Lyford.

Civil Defence posted on Facebook a helicopter had not been able to fly ahead of the convoy to assess risks.

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But Canterbury Civil Defence spokesman Neville Reilly said the convoy was back on track mid-morning after the weather delay.

He said each day the road was checked by air to see if any new cracks or landslips had developed overnight.

Today's deteriorating conditions meant it couldn't be done by air and a vehicle was sent ahead by road to check the damaged route.

The convoy had reached Mt Lyford.

"We now have the word that the road is safe so the convoy will now start moving to Kaikoura," said Reilly.

He said it was expected to take another three hours before the convoy arrived in the cut-off township, about 40km away.

Reilly said the weather was overcast and wet and fog shrouded parts of the route.

The army's 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.

Earlier the Kaikoura District Council Civil Defence tweeted the convoy has been delayed by deteriorating conditions.

The Inland Rd to Kaikoura is closed to all traffic except the military.

Large landslides caused by last week's earthquake 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.

Today is the fourth mission. The journey is taking up to 3.5 hours each way. Road contractors and engineers stop their frantic work in opening up the road to allow the convoy to pass.