National temperature records could fall this week.
Parts of South Australia are expected to nudge 50 degrees, while Melbourne will nudge 40 on Wednesday and hit at least 41 on Friday.
Tasmania will warm up by Friday but a weather system bringing up strong westerlies from Antarctica will see temperatures here stay well below those being experienced interstate.
The Bureau of Meteorology's Glen Perrin predicting Tasmania to see temperatures hover in the thirties.
"Friday we are expecting temperatures in the 30 to mid 30 degree range, especially in the south and east, it will be quite a warm day on Friday."
"It will be a very hot temperature range so we will certainly going to get quite warm temperatures, but not in the same degree as the mainland. So we're not expecting anything in the range of 40 degrees plus," he said.