A heatwave alert has been issued for the general Wagga Wagga area from Wednesday until Friday this week.
The temperature is forecast to reach 39 degrees celsius tomorrow, 40 degrees on Thursday and 41 degrees on Friday.
The Riverina Murray Emergency Management Region says residents outside the general Wagga area should also monitor local conditions until the heatwave is over.
The Murrumbidgee Local Health District's Disaster Manager Denise Garner says people should drink plenty of water, keep cool, take care of others and have a plan should problems arise.
Those most at risk of succumbing to heat are people aged over 75, babies and children, the overweight or chronically ill, those who live alone and outdoor workers.
© ABC 2013
11:39 EDT El Nino is one extreme of the El Nino-Southern Oscillation (ENSO) phenomena, in which La Nina is its counterpart.