Lost pair spent nearly two weeks without food in Kahurangi National Park

The two trampers who went missing in bush north-west of Nelson say they spent nearly two weeks without food and their only saving grace was water they had found.

An intensive search and rescue operation had been underway to find Dion Reynolds and Jessica O'Connor, who have been in Kahurangi National Park since 8 May.

The pair were in a very rugged and remote part of the park when a search helicopter spotted smoke from a fire they had lit and rescued them yesterday, the police officer leading the rescue, Sergeant Malcolm York, said.

York said the 23-year-olds were incredibly lucky to have survived.

"This search was a particularly challenging one due to the remote and rugged location, it's a long from anywhere out there and it's a complete lack of any communication."

Despite spending the night in a comfy bed in a long while, Dion Reynolds said he "couldn't sleep a wink" because it was hard to process everything that had happened.

Reynolds told Morning Report they had gone into the bush on 8 May, rather than their planned 9 May date.

"We went up the river for two days and made our first campsite, and pretty much the first thing that started going wrong is we ended up burning our socks, I burnt three out of the four socks that I'd had after the river crossing."

The next day as they carried on they realised they had made more progress than they expected to, he said.

"We looked at our map and what we thought was the waterfall that we got to wasn't what we got to really. We decided to go up the hill and thought we'd cut across the track and carry on down towards the lake. The next day once we camped up on that hill, the fog had come in and it really disorientated us.

"We thought we were going to just carry on heading east up the hill in the same direction that we were, but obviously it wasn't."

After they had passed through a forest, Reynolds told Jessica that they needed to stop because he realised they were going around in circles.

They decided to camp there and it was another couple of days of fog but they were running low on water, he said.

"We were on top of a hill, there was no fresh clean water. Jess had gone to this little rocky puddle that we ended up boiling the water out of, and that was all right for us.

"The next day we kept on going until we found this hilltop and the fog was still there."

Once the sun came out, they decided to get a sense of where they were to find fresh water, Reynolds said.

"We only had two days worth of food left and we were going down a gully, real steep, it turned from a small rocky stream into pretty serious waterfall. On our way down, I twisted and sprained my ankle... we got to a waterfall that was 15-20m high and we just looked at each other were like 'we can't go down that, we need to stop and go back up the hill and stop'."

Once again, they made camp and waited it out but Jessica had also injured her back after falling while trying to get water, Reynolds said.

"We were very lost at this point."

They spent 13 days without food, but the "saving grace" was a stream of water that was two minutes away from the gully, he said.

"That's what kept us alive."

Jessica had contacted her family prior to the trip to assure them that they'd be definitely be back by her birthday. But as time passed, the pair relied on each other not to break down and made sure not to lose hope.

"It was a real surreal experience, trying to keep positive, trying to keep hopes up.

"Jess and I would wake up in the morning and think if it's not today, it's tomorrow, and if it's not tomorrow, it's the next day."

About a week ago, he said they spotted a helicopter flying over and lit the fire again to grab its attention.

"It got to about what I assumed would be five-thirty or six o'clock in the evening and we saw a Westpac Rescue helicopter fly up the gully and straight at us... and they just didn't spot us because it was real poor lighting. After that, it really bolstered our hopes a whole lot."

The rescuers finally managed to locate them and went down to them.

"I've never been so God damn happy in my life ... First chopper came over and saw us and Jess went over the quarry and started waving at it.

"Then the medic came down... At that point I knew we were saved."

When they were winched up, Reynolds said he saw where they were camped and it was not where they had thought they were.

About 10 minutes into the ride, he said they got the "best chocolate bars I've ever had in my life."

Reynolds' family celebrated his return with drinks and pizza in Nelson last night.

'Impressive to watch it all unfold,' rescue pilot says

An Air Force pilot who helped rescue the pair, flight Lieutenant Loic Ifrah, said they were so well hidden beneath the trees it was incredible that the search helicopter had managed to locate them.

"Even though I was looking exactly at the spot, looking down into a hole in the trees, I could barely make out two human beings," Ifrah said.

"Pretty incredible spot by the crew and a big effort from the Land SAR volunteers and police to coordinate all that. It was pretty impressive to watch it all unfold."

A paramedic was winched down to check on their condition.

"They shared in a group cuddle - they'd definitely been isolated for their 14-day period and our medic was pretty pleased to see them and they were pleased to see [him]."

"We left him on the ground with the pair for about 10 minutes and in that time he carried out his medical assessment ... and we winched them up."

Though he was concentrating on flying the helicopter, Ifrah said he shared their relief.

There were times when it seemed like they wouldn't be able to find the missing pair, he said.

"We hadn't given up obviously, because we wouldn't have put our efforts into it but as time goes by, and poor weather comes and goes, thoughts always do turn to the worst.

"I guess that adds to the relief and euphoria at finding them alive and well."

Despite the day's success, his crew had to get an early night.

They will be heading out this morning to pick up the 13 remaining searchers and two dogs who spent the night in the national park.