Dramatic hillside collapse captured on video during Nelson's severe flooding

A Cambridge couple are swapping their running shoes for shovels as they clear a mudslide that has ended up on the doorstep of the property they're minding for friends.

Gary Fieldes and partner Annie are almost halfway through a two-month house-sitting stint on behalf of friends who are away in the US.

The retired couple had planned to spend a lot of time running in the hills but instead have found themselves caught up in Nelson's weather emergency.

They were set to evacuate their friends' property at Marybank, 6km north of Nelson, on Thursday.

Fieldes grabbed his phone when he noticed the hillside above the house was starting to move and managed to hold his nerve to capture much of the hillside collapsing.

The footage, posted to Facebook, has been viewed hundreds of times with comments ranging from "mesmerising and terrifying" to "this is so sad for Nelson".

"We're pretty lucky - the house is perfectly fine," Fieldes said on Monday.

The couple changed their minds about leaving on Thursday despite the downpour that was occurring because while the slip stopped at the letterbox a lot of surface water poured over the property and down into a neighbour's.

"So we dug trenches for three solid hours on the Thursday and ended up staying here at night."

It was a scary time because another big slip was threatening to move above the first one so the couple had to keep "an anxious eye" on it but it did not budge.

On Friday geotech workers advised them to leave so they spent two nights away before returning yesterday.

Fieldes has been able to tell his friends that their house has escaped relatively unscathed with just plenty of mud to be cleared away.

He said it has been a relief for their friends to have constant updates on what has been happening.

He was also grateful the council has cleared half of the road so they can access the property and hoped that it would finish the job in the next few days.

RNZ