Young Britons survive bush 'nightmare'

Two young Britons believe they're lucky to be alive after getting lost on a day walk in dense New Zealand bush and spending the night huddling next to a waterfall as temperatures dropped below zero.

Backpackers Stephanie Baker and Ryan Millward, both 23, say a wrong turn during an eight-hour hike through Mount Richmond Forest Park near Blenheim landed them in deep water, literally.

"I'm feeling like I'm lucky to be here right now," says Ms Baker, exhausted after finally getting out of the park at 5am on Monday.

"We were wet, freezing, had no food and we were miles from anywhere. It was a nightmare. If it hadn't been for my phone and the people who came to get us ... they saved my life," she told AAP.