Multiple states and territories are set to swelter into the new year as a heatwave grips much of northern Australia.

Parts of Queensland, the Northern Territory and Western Australia have been put on alert with temperatures forecast to be 8C to 12C above average.

The Bureau of Meteorology issued a heatwave warning for the NT, Queensland and WA while the south faces milder weather. An extreme heatwave warning was in place for the NT’s Tiwi district and Kimberley, Pilbara and North Interior districts in WA.

Temperatures in remote towns Marble Bar and Roebourne, in the northwest of WA, were expected to reach 48C on Sunday.

Most towns in the NT’s Barkley region were expected to tip the 40C mark.

While a severe heatwave warning was in place for parts of Queensland, elsewhere severe thunderstorms had emergency services on high alert.

Communities from Charters Towers to Emerald in northern Queensland were warned to brace for heavy rain, possible flash flooding and potentially giant hailstones.

Australia is currently under the influence of the El Nino phenomenon, which can cause weather extremes ranging from wildfires to cyclones and prolonged droughts.

Mild weather is forecast for the southeast, including Sydney, on Sunday as Australia’s biggest city gears up for New Year’s Eve celebrations.

Tens of thousands of people are expected to flock to prime harbourside spots to watch the city’s famous fireworks.

Brisbane’s official NYE program has not been altered despite heatwave conditions.

Source: AAP, Reuters