Heatwave conditions forecast for the mid north coast today have sparked a warning from NSW Ambulance.
Paramedics say people need to try and stay cool and hydrated with temperatures likely to be in the high 30s.
Ambulance spokeswoman Jackie Levett said extremely hot weather can be life threatening but simple precautions can prevent any problems.
"If the body has to work too hard for too long to keep itself cool people can become very unwell,' she said.
"The signs of heatstroke include headache, weakness, vomiting and dizziness.
"People are being reminded to perhaps reschedule and unnecessary activity particularly in the hottest part of the day.
"We also remind people it's quite important to drink water, regularly, in small amounts throughout the day."
Miss Levett said people should take heatwave conditions very seriously.
"Temperatures are expected to reach 39 degrees on the mid north coast," she said.
"So NSW Ambulance has a warning to people in the community that these conditions can possibly lead to life threatening situations.
"Heat can kill with sunburn, dehydration and heat exposure leading to heat stroke."
© ABC 2013
20:25 EDT A dwindling number of volunteers is collecting some of the weather bureau's most important data from across South Australia.