Three adults with a toddler in tow have suffered heatstroke after attempting a walk without enough water in the sun-bitten Central Australian bush in the middle of a 45C day.

Key points: NT rangers have put out a warning to bushwalkers following two separate incidents of hikers getting into trouble

NT rangers have put out a warning to bushwalkers following two separate incidents of hikers getting into trouble Three adults and a toddler suffered heat stroke while a couple from Melbourne became lost with just a small bottle of water

Three adults and a toddler suffered heat stroke while a couple from Melbourne became lost with just a small bottle of water Heatwave in Central Australia continues to hit record-pushing temperatures above 40C

With the mercury pushing well past 40C across the region, from Alice Springs to Yulara and Tennant Creek, bushwalkers have been urged to rethink their plans.

Northern Territory park rangers put out a stark warning pleading for tourists to heed advice and not put their lives at risk during the heatwave after two lucky escapes.

On Friday, the three tourists from the Philippines, travelling with a three-year-old, suffered heat stress while walking in the middle of the day at Standley Chasm in the West McDonnell Ranges.

In a separate incident, rangers said a couple from Melbourne took a wrong turn at Simpsons Gap and ended up on a longer trail with only 600ml of water between them.

Parks and Wildlife's Kristen Hay warned visitors to Central Australian parks "to consider postponing their walks or to walk very early in the morning when it's cooler".

"Even if you are an experienced walker you must take precautions when visiting Territory parks," she said.

"Walking in hot weather can result in heat exhaustion, which may progress to a potentially fatal heat stroke."

In February 2017, German tourists Wilfred and Gisela Thor tragically perished from heat stress and dehydration in the East McDonnell Ranges after wandering off a marked trail at Trephina Gorge.

Hot conditions to continue

Bureau of Meteorology forecaster Jackson Browne said records were being broken across the Red Centre region.

Near Standley Chasm, in Central Australia, where a group of hikers nearly fell into trouble. ( ABC News: Steven Schubert )

"On Saturday we saw Alice Springs break its all-time temperature record with 45.6 degrees," Mr Browne said.

"And on Sunday night we saw Walangurru or Kintore community near the Western Australia border break the highest minimum temperature for the NT."

In the Top End, hot conditions were also predicted to continue, as a cyclone threatens to steal Darwin's expected monsoon.

"These cyclones tend to concentrate and shrink all the weather around it," Mr Browne said.

So that is what is happening with this monsoon.

"Darwin's just lucked out."

This system was expected to intensify in the early hours of New Year's Day and will be named Tropical Cyclone Penny.