SYDNEY (DPA) - As Australia's heatwave dragged into its sixth day on Friday (Jan 18), heat records were broken and roads were melting.

At Wauchope, 373km north of Sydney, bitumen was reported melting on the main highway, causing road workers to spray water to cool the surface so that it would not stick to car tyres, the local Argus newspaper reported.

Heat records were broken across eastern Australia as temperatures soared in the high 40s on Friday.

It was not just the sun breaking records - Australia's highest night-time heat record was smashed on Thursday (Jan 17) at Noona, 800km west of Sydney, where the lowest overnight temperature was 35.9 deg C.

Mr Blair Trewin of the Bureau of Meteorology said it was the hottest night ever recorded in Australia.

"We have now seen five days in a row with temperatures widely well into the 40s," he told the national broadcaster ABC. It is the hottest January period since 1939.

Forecasters said conditions should ease over the weekend before ramping up again next week.

"There are some indications of another round of extreme heat towards the end of next week," Mr Trewin said.