Abseilers brave the steep, and the heat, to stabilise cliff faces south of Kaikōura ahead of SH1 reopening.

Working 100 metres up, dangling from a rope on a cliff face for up to 10 hours a day might sound terrifying.

But for these "super human" abseilers, it's just another day on the job.

Damian Christie took this footage south of Kaikōura on Thursday, ahead of State Highway 1 opening between Picton and Christchurch on Friday.

Damian Christie / Supplied In this job, you cannot be scared of heights.

"It looks like such an intense job," he said. Shooting from a distance, the workers "look like tiny ants... it shows the scale of it," he said.

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On Thursday Kaikōura hit a high of 21 degrees Celsius. They were back out in 29C on Friday.

Damian Christie / SUPPLIED Abseilers complete rock stabilisation and mesh work above State Highway 1, south of Kaikōura.

Their work involves drilling and fixing giant anchor bars metres into the rock, then pinning geomesh over the cliff face to stop rocks falling on the highway below.

South Earthworks project engineer Melissa Sheridan said there were 10 big abseiling sites along the stretch of earthquake-affected highway, as part of the North Canterbury Transport Infrastructure Recovery (NCTIR) alliance project.

This one was the second biggest, involving fixing more than 5000 square metres of mesh to the cliff face.

"You can imagine it's quite a difficult operation," she said.

At the moment there were about 79 abseilers from six companies carrying out road protection measures across the various sites.

"They're little super humans, she said.

"They won't put themselves in an unsafe position, but you need to have your wits [about you] and be somewhat without fear."

Needless to say, vertigo is not an option.

"One of the questions [to get certified to work at heights] is 'do you have a fear of heights'. Everyone smiles and says no," she said.