A 16-year-old boy has been found dead in a creek after becoming separated from his friend, who was winched to safety from a remote campground described as one of the most secluded wilderness areas in the Blue Mountains, west of Sydney.

NSW Police have been told the 16-year-old and another boy, aged 17, were walking to Mount Hay from Leura train station, with their trip expected to last three days.

The pair set off from the train station on Tuesday.

The older boy activated a personal locator beacon about 5.45pm on Wednesday after the two became separated.

The beacons can be hired for free from the state’s National Parks and Wildlife Service, but are also sold in camping supply stores and send a distress message via satellite with a GPS location.

The 17-year-old was winched by a rescue helicopter from Acacia Flat camping ground in the Grose Valley Wilderness area several hours’ walk from Leura train station.

The campground is described on the NSW National Parks website as one for “intrepid campers” at the end of a “challenging, very steep” track, but it is not yet known which route the teens took to the area.

A search for the 16-year-old, involving local police, the Blue Mountains Rescue Squad, NSW Ambulance, PolAir and the Toll Rescue Helicopter, ended about 1pm on Thursday.

The boy’s body was found in a creek in Blue Gum Forest, within the Blue Mountains National Park.

A report is being prepared for the coroner with a post-mortem examination to determine how he died.

Graham Reibelt, co-founder of award-winning tourism information platform Ask Roz Blue Mountains, said tracks are sometimes difficult to distinguish.

“They may have gone off track, but certainly that whole area is very hostile,” he said.

“After the fires went through, the vegetation has come back quite viciously, a lot of weed.

“In that area, [tracks] are really self-maintained, with sufficient walkers going along there that it defines the track.”

Reibelt said people should file trip intention forms with the NSW National Parks and Wildlife Service before setting off in the Blue Mountains, advising how long they plan to be gone and who to contact if they don’t return.

“It wouldn’t have made a difference in this case, because they weren’t late,” Reibelt said.

“An accident can happen at any time.”

People have fallen off tracks, or had them disappear underneath their feet due to land subsidence. They break bones, fall and hit their heads, get bitten by snakes or become separated easily.

“You can be 10 metres away from someone and not know where they were. You get disoriented.” Reibelt said.