Prime Minister Scott Morrison has fielded offers of support in the bushfires from world leaders, including United States President Donald Trump.

The US leader called Mr Morrison on Tuesday to offer his support to Australia and all the bushfire-affected communities, and the prime minister thanked him for the support the US has already provided in the form of firefighters.

President Donald Trump has called Prime Minister Scott Morrison to offer his support in the national bushfire crisis. Credit:Bloomberg

Mr Morrison also spoke with Fijian Prime Minister Frank Bainimarama, who offered his support and condolences to Australia, and has received messages from UK Prime Minister Boris Johnson and Solomon Islands Prime Minister Manasseh Sogavare.

New Zealand has already sent firefighters to help fight the Australian fires, along with Canada and the United States.

Papua New Guinea has also offered firefighters and defence force officers, while Singapore's Chinook helicopters, based in Australia, are being used in the relief effort.