Scientists have warned that hundreds of Australians could die in the coming months as a powerful 'super El Niño' pushes temperatures well above normal.

Researchers from the Climate Impact Lab forecast an additional 260 heat-related deaths across Australia between September and February, with almost half expected to occur in NSW.

The weather event is expected to drive temperatures about 1.2C above normal during the six-month period.

The report, which was released on Tuesday, also predicted there would be 61 additional heat deaths in Queensland, 72 deaths in Western Australia, 12 deaths in South Australia, and three additional deaths in the Northern Territory.

However, there will be a net decrease of 13 heat deaths in Victoria compared with data from 1996 to 2025.

It comes as authors Michael Greenstone, Tamma Carleton, Genevieve Maricle and Emily Grover-Kopec forecast an extra 451,000 people will die worldwide in the first nine months of the super El Niño.

'El Niño is effectively pushing us into the future – exposing us to temperatures that won't be the norm for another two decades – before we have time to adapt and protect ourselves,' they said.

'These anomalously warm conditions will resemble the higher temperatures that climate change is projected to deliver 20 years in the future. 

'With current forecasts suggesting El Niño will remain in place through spring 2027, we expect all of these numbers to grow even higher, particularly as impacts such as higher-than-average temperatures and heat-related deaths will linger into June and July.'

The authors also warned El Niño will lead to 44 per cent more 'extremely hot' days than we would usually expect in a normal year.

They also flagged that the nations to be hit hardest by the record weather event will be in poorer regions, such as the Sahel in Africa, where 31,400 people are expected to die in Nigeria alone from this month to February.

Similar figures are predicted for parts of Asia, such as Indonesia, which is forecast to have an additional 19,300 deaths, as well as Sudan with an extra 17,500 deaths, India with 15,800 and Brazil with 13,300.

'The anomalously warm temperatures that most of the globe will see during this El Niño event are a 'postcard from the future'; while they feel anomalous now, they will become normal just a few decades into the future,' the authors said.

'Mortality projections for the near term provide a signal of where we are headed if new adaptation investments do not materialise. The difference with climate change is that there is more time to undertake adaptations to save lives.'

The report called for emergency funds to be redirected to the worst-affected areas and suggested heat warnings, health outreach to vulnerable populations, cooling centres and hydration stations, and worker protections to help people cope with extreme heat.

'We need to build the evidence base now for what works and then invest in preparations and planning,' the authors said. 

'Preparing for a hotter future will require a far more granular, continually updated understanding of what saves lives across different regions, climates, and health systems.'

The Bureau of Meteorology says temperatures are likely to remain above average across most of the country through the end of the year, while its climate models indicate the developing El Niño could become the strongest on record. 

- READ MORE: 'Supercharged': El Nino brings drier, hotter conditions