A German tourist rescued after being lost on Mt Taranaki for three days has described her joy when her cries for help were heard.

Theresa Schaaf, who is from Darmstadt, near Frankfurt, was reported missing on Monday morning when her travelling companion, returned from a tramp to discover she was no longer at their car.

More than 40 rescuers searched for the 19-year-old today, including Land SAR staff from Taranaki, Whanganui and Palmerston North, Department of Conservation (DOC) workers and Air Force personnel.

A DOC worker out counting whio found Ms Schaaf shortly after 11am.

The teenager said she was lost in dense bush when she was discovered.

"I was more or less forcing my way through a track that wasn't prepared for walking. There was lots of wood and trees that had fallen over, so it was getting harder to move on.

"I was yelling for help every 100m, in the hope that someone would hear me and somebody answered.

"It was a nice feeling, because I hadn't heard anyone in three days and he got me back."

Photo: RNZ / Robin Martin

Ms Schaaf said she decided to go for a walk on the Ngatoro Loop Track because she was "bored" waiting for a friend.

"I decided to do a track and it was supposed to be four hours, but I got lost and it's gone on more than four hours."

She had only a packet of Skittles and a bottle of water for sustenance.

"I had some sweets, but not really anything to that could sustain you that long. So I was getting a bit worried about the lack of food.

"I was moving very slowly because I was aware that my skills, my reflexes were getting worse because I hadn't eaten or drunk that much."

At night, a makeshift hut was her only shelter.

"I built a little shelter out of sticks and ferns and I put tissues around my shelter so people could see them from a far. It was pretty cold."

Photo: RNZ / Robin Martin

Ms Schaaf thought her friend would have raised the alarm, but did not hear any searchers so she kept moving - something Land SAR staff had since told her was a mistake.

With rain coming in over the mountain, the teenager said she was grateful to have been rescued.

"I was very careful when moving, because injuring myself would've been the end. Basically I would've needed to wait for someone to get me and by that time I was aware people were searching on the wrong tracks."

Ms Schaaf said she had learned some valuable lessons from her experience.

"While I was walking I was considering writing my own book about how not to get lost in a forest . You should charge your phone before going into a forest, you should bring more water than you need, as well as food, and be prepared for anything."

Photo: RNZ / Robin Martin

Her travel companion, Paula Frohlich, said she had become more and more concerned about her friend.

"Today was not such a good day because at the beginning I was quite calm and I thought, you know, somebody will find her, but as time went on it just got more difficult."

That all changed when news came through Ms Schaaf had been found.

"That was a real relief, because when you know nothing you just imagine everything, and so I was just really happy."

'People were jumping around pretty excited'

Area Commander Keith Borrell, who coordinated the search, had no problem with Ms Schaaf heading into the bush alone.

"The biggest thing for us is that if you go even for a small walk in this national park you tell someone of your intentions and this is what she didn't do on this occasion.

Photo: RNZ / Robin Martin

"So if she had gone up to the visitors centre and written into the intentions book where she was going to walk, it would've given us a better clue where to look once she went missing."

Mr Borrell said concerns were growing for Ms Schaaf's safety.

"The longer the search went on the more concerned we were getting because she wasn't prepared equipment wise to stay overnight in the bush and with the weather closing in."

The rescue team was happy the teenager had been found safe and sound, he said.

"The biggest thrill you can get is when you hear the missing party has been found. I was in the search headquarters at the time and people were jumping around pretty excited and we've just had a debrief with the staff in the field and they were feeling the same."