Record temperatures have forced the Australian government's weather bureau to increase its scale to 54C to reflect the extreme highs forecast for next week.
The temperature in parts of central Australia could soar to above 50C next Monday, according to the Bureau of Meteorology (BOM).
Head of climate monitoring and prediction David Jones said the new scale, which features a purple and pink colour code for temperatures from 52 to 54C, shows there is potential for records to be smashed.
"The scale has just been increased today and I would anticipate it is because the forecast coming from the bureau's model is showing temperatures in excess of 50 degrees," Mr Jones told local newspapers.
Australia's all-time record temperature is 50.7C, set in January 1960 at Oodnadatta in the state of South Australia.
The nation as a whole experienced its hottest day on record on Monday with the average maximum temperature across the country hitting 40.33C, surpassing the previous mark of 40.17C set in 1972.
More than 100 fires blazed in New South Wales, Australia's most populous state, where officials described the heat, wind and dry vegetation conditions as among the worst the state had ever seen for bushfires.
"We had the hottest day on record for Australia (on Monday) and today it looks like we may well go better again," said Mr Jones.
"This really puts the national dimension of this heat event into bigger context."
Speaking about devastating bushfires that razed 100 homes in the southern island state of Tasmania at the weekend, Prime Minister Julia Gillard warned this week that Australia would see more extreme events due to global warming.
"Whilst you would not put any one event down to climate change, weather doesn't work like that, we do know over time that as a result of climate change we are going to see more extreme weather events and conditions," Ms Gillard said.