Large swaths of Australia on Sunday sweated through heat wave conditions as authorities warned of a high bushfire risk in many parts of the country's vast Western Australia state.

The nation's weather forecaster on Sunday issued heat wave alerts for the state and neighbouring Northern Territory, warning temperatures in some regions could hit around 45 degrees Celsius (113 degrees Fahrenheit).

In Perth, the capital of Western Australia, the nation's largest state, a maximum temperature of 35 C (95 F) was forecast for Sunday, more than five degrees above the December mean, forecaster data showed.

Australia's east is scorching due to El Nino, a climate pattern in which unusually warm Pacific Ocean temperatures cause heat waves, cyclones, droughts and wildfires.

In Western Australia, more than 20 bushfires were burning on Sunday, the state's emergency services agency said on its website, including an uncontrolled one near Pemberton, a town of around 5,000 residents, about 320 km (198 miles) south of the state capital Perth.

State authorities on Sunday warned of a high fire danger for many parts of Western Australia, a mining state covering the western third of the Australian continent.

(Reporting by Sam McKeith in Sydney; Editing by Richard Chang)