Even getting to the rescue site was difficult for rescuers, Mr Nicholson said.
"There was a lot of debris on the road as a result of the weather conditions. About 2km from where the pair was on the other side of the river a large tree had been blown across the road completely blocking the highway. The rescue team used hand saws to cut the tree's branches and pulled branches off the road with their 4x4 vehicle to get access to a point where they could potentially undertake a rescue."
The team used an inflatable raft to ferry the stranded pair back to the roadside.
Mr Nicholson praised the couple's decision not to try to cross the river.
"These two did the right thing by not trying to swim across the river. Given the poor weather conditions at the time and the amount of water that was pumping we would have certainly had a fatality on our hands if they had tried to swim the river," he said.
The couple were on a six-month working holiday in New Zealand and due to leave for the United States next week. They were both cold but otherwise in good spirits after their ordeal.
Last month a Canadian couple were killed when their campervan was swept into the flooded Haast River by a landslip during a storm.
The body of Joanna Lam was later found but that of her boyfriend Connor Hayes is still missing.