Frequent, urgent warnings from Northern Territory police, paramedics and park rangers to avoid hiking during a scalding Central Australian heatwave continue to go ignored.

Key points: NT Police rescued a bushwalker from the Larapinta Trail, west of Alice Springs

NT Police rescued a bushwalker from the Larapinta Trail, west of Alice Springs It came the same day as rescuers called off a search for a German tourist, who went missing

It came the same day as rescuers called off a search for a German tourist, who went missing Paramedics are warning that those risking the dangers of hiking in the heat are also putting rescuers in harm's way

Northern Territory emergency services have again pleaded with members of the public not to put themselves at risk from the conditions after they had to rescue an experienced local bushwalker.

The 60-year-old bushwalker had to be rescued by NT Police on Sunday about two kilometres from Simpsons Gap, west of Alice Springs, while hiking the first section of the rugged Larapinta Trail.

She was with a bushwalking group when she sustained an ankle injury and became dehydrated, according to Andrew Everingham, the St John Ambulance southern region manager.

"It looks like she was overcome by some of the extreme heat on that day and she became unwell, quite dizzy and needed assistance," he said.

Still unsafe despite experience

The woman became ill even though she was an experienced bushwalker who was well prepared for the conditions, Mr Everingham said.

"Despite being well equipped and having the appropriate knowledge and experience, we're experiencing some extreme heat events," he said.

Paramedics are warning hikers to rethink their walks as a heatwave continues. ( ABC News: Shelley Lloyd )

"It's never safe to walk under those conditions in those kind of locations.

"You're not only putting yourselves at risk but you're also putting the rescuers who have to come and assist you at risk."

Alice Springs Airport, south of the town, recorded 42.2C at 4:30pm, the third day in a row the temperature hit more than 40C.

The rest of the working week was forecast to hit a top of at least 40 degrees in Alice Springs.

Monika Billen still missing

The incident came off the back of an exhaustive outback search for missing German tourist Monika Billen, who was believed to have gone hiking in remote Emily Gap in the East McDonnell Ranges sometime around New Year's Day.

Police searching Emily Gap, near Alice Springs, for missing tourist Monika Billen. ( ABC News: Katrina Beavan )

Five days of searching by foot, vehicle, motorbikes, horseback, helicopter and drone has failed to find a trace of the 62-year-old.

Land and air searches were called off on Sunday.

The temperature at the airport reached 43.5C on the day Ms Billen was last seen alive.

Earlier in the summer, two groups of tourists were found suffering from heat stress on walking trails in remote Central Australia, including a three adults with a toddler.

Just one year after German tourists perished

Ms Billen's disappearance comes just months after a coronial inquest found two German tourist may have died from dehydration and heat stress before an alarm was raised they were missing in 2017.

Wilfried, 76, and Gisela Thor, 73, left their accommodation in Alice Springs at 6am on February 10 last year to travel to the East MacDonnell Ranges.

They too had planned to travel to Emily Gap, as well as Jessie Gap and Trephina Gorge, near where their bodies were eventually found.

Only a few hundred metres into the journey they missed arrows that would signify the track, and wandered off the path and out of the national park.

Their bodies were discovered days later.

After the deaths of the Thors, a Parks and Wildlife review found a number of issues including the absence of the boundary fence, the adequacy of the signage and track marking, the adequacy of safety messaging available to visitors before visiting the park, the failure to immediately commence a search on initial notification and the lack of mobile or Wi-Fi coverage.