SYDNEY (Reuters) -Large swaths of Australia on Saturday sweated through severe heatwave conditions that lifted bushfire risk in the country's southeast.

The nation's weather forecaster on Saturday had heatwave alerts in place for South Australia, New South Wales, Tasmania, the Australian Capital Territory and Victoria, warning temperatures in some regions could go above 40 degrees Celsius (104 degrees Fahrenheit).

In Victoria's capital Melbourne, a maximum temperature of 39 C (102.2 F) was forecast for Saturday, more than 15 degrees above the March mean, forecaster data showed. It was 31.5 C at 11.10 local time on Saturday, the forecaster said.

"Extreme fire danger is forecast for Central and South West districts, including Melbourne and Geelong," it said on social media platform X.

In New South Wales, Australia's most populous state, there were 19 bush and grass fires burning on Saturday, according to the state's Rural Fire Service agency website.

A senior meteorologist at the forecaster, Sarah Scully, told the Australian Broadcasting Corp that hot weather would likely continue until Tuesday "when a much colder air mass and southerly change is forecast".

Australia's summer was gripped by an El Nino weather pattern, now easing, in which unusually warm Pacific Ocean temperatures cause heatwaves, cyclones, droughts and wildfires.

In February, tens of thousands of people had to evacuate amid an intense heatwave and massive bushfire in Victoria, which faced its worst conditions in four years.

(Reporting by Sam McKeith in Sydney; Editing by David Gregorio and Diane Craft)