Elderly people, young children and pregnant women are among those who can be worst-affected by heat.

In guidelines on how to keep cool, the Red Cross advises:

Drink water even when you don't feel thirsty

Avoid alcohol, tea, coffee and fizzy drinks, as they can dehydrate you

Eat small meals more often and cold food like fruit

Stay indoors

If you need to go outside, wear a hat and sunscreen and bring water. Try to go early in the day

Humidity levels reached more than 70 percent on Saturday and Sunday in Boorowa.

Temperatures are not expected to drop below 35 degrees for the rest of the week, with a high of 41 degrees predicted for Friday.

The weather bureau predicts temperatures will hover around the mid 30s for the weekend.

There is a 60 percent chance of rain on Friday.