Survival triumph: The 'incredible piece of searching' that unearthed missing trampers' location after 19-day ordeal

Hungry and exhausted after a 19-day ordeal lost in "hostile" thick bush, a young couple were plucked from a tiny 3m clearing after their fire signalled a helicopter above.

And after being winched aboard a Defence helicopter this afternoon deep in Kahurangi National Park, Jessica O'Connor and Dion Reynolds devoured chocolate bars and enjoyed a "group hug" with their rescuers.

The pair, both 23, entered the bush on May 9 but became lost early on in their tramp due to fog. It's believed they spent about two weeks hunkered down in rugged terrain, desperate for water and running out of food.

The terrain where trampers Jessica O'Connor and Dion Reynolds were found in the Kahurangi National Park after being missing for 19 days. Photo / Supplied

Despite both suffering injuries during their dramatic ordeal, they survived freezing temperatures, with rescuers crediting the pair's "excellent equipment" for keeping them alive.

O'Connor's parents "burst into tears" at the news their missing children had been found.

Mark O'Connor said they spoke to their daughter briefly after the rescue by phone from her hospital bed.

"She literally just said, 'Hey mum and dad, it's Jess!', so we'll learn a bit more but apparently they're both in good shape so that's good," he told TVNZ.

"She was very emotional," her mother Simone said.

"I think she was in tears and couldn't talk much so that was about it really, we will talk more once we see her."

While the O'Connors spent "many sleepless nights" worrying about the missing pair, Simone said she never doubted they would be found alive.

After the pair failed to emerge as expected they were reported missing on May 18 and a massive search operation was launched.

Searchers initially had good weather on their side but the search was suspended over the weekend due to heavy rain, reducing the odds of the pair being found alive.

They were finally located shortly before 1pm in the Anatori area, prompting smiles and relief from rescuers.

Royal New Zealand Air Force flight lieutenant Loic Ifrah said coordinates from a civil helicopter who first spotted the stricken pair led him straight to the spot where the trampers waited below.

The pilot said it was a "incredible piece of searching" that had unearthed their location in a small clearing behind a dead tree.

"I knew exactly where to look and looking down into that hole, I still couldn't see them."

The clearing was roughly 3 by 3 metres, not much bigger than a car, with overhanging branches which they had to winch people around, he said.

They carefully lowered a medic down to see them using a winch.

"They had been in isolation for long enough that they could afford our search and rescue medic with a nice group hug," he said.

The helicopter had been hovering 150 feet above steep terrain which he admitted was not the easiest job but one they were well trained for.

Once on board the young trampers were given chocolate bars by friendly crew members, he said.

"I think they were very happy to see us."

Ifrah said the job was not quite finished as they had run out of time to pick up all of the searchers in the area.

"We are obviously over the moon that they have been found safe and well and that they can rejoin their families.

"We are back into it tomorrow to recover the other search teams."

He heaped praise on the civilian helicopter crew who discovered the missing pair's location, as well as the huge efforts from police and Landsar volunteers.

O'Connor and Reynolds first set off near the Anatori River carpark on May 9.

Shortly after midday on May 12, O'Connor sent a text confirming she was safe in the bush.

But they lost their way in fog early in the tramp.

At some point Reynolds injured his ankle and O'Connor strained her back in a fall.

After the fall the pair stayed put for number of days until they needed water.

It's believed the pair had been without food for some time.

They were hungry and exhausted but relieved to see their rescuers.

Nelson Bays Area Commander Paul Borrell said it was the "fantastic outcome" they had hoped for, even in the face of increasing concerns as the days passed.

"I am so very, very proud of our Search and Rescue team made up largely of volunteers and supported by police."

The pair seemed to be in good condition considering it had been a 19-day ordeal in "such a hostile environment", Borrell said.

Nelson police search and rescue co-ordinator Sergeant Malcolm York said: "This search was particularly challenging being such a remote rugged, bush-clad area."

Up to 50 people including police, NZDF, search personnel and other volunteers had all desperately wanted to return the pair safely to their families, he said.

"Such outcomes are always totally dependent on the cooperation and hard work from a wide range of dedicated people ... from a number of organisations including police whom I want to sincerely thank."

York said it was "pretty rare" to have such a positive outcome after such a long search.

"They did the right thing, they stayed put, and they made themselves visible, so when we got to that spot, we were able to see them."

Royal New Zealand Airforce NH90 helicopter and crew helped searching for missing trampers Jessica O'Connor and Dion Reynolds. Photo / supplied

He said the pair had excellent equipment that kept them alive in cold conditions.

"They've done well to survive. Just the fact that after 19 days they're in such good condition ... it shows they've done the right thing."