About 35 American firefighting operation chiefs, aviation managers, planning section chiefs and specialists in land rehabilitation will fly to Australia.

"Australia and New Zealand have been wonderful neighbours and provided help in our time of need and we are happy to return that help," US National Interagency Fire Center spokesman Don Smurthwaite said.

Australia, New Zealand and US firefighting agencies have a close working relationship and have participated in exchange programs in recent years.

On the weekend Australian and US government officials held informal discussions about calling on American fire personnel.

A formal request for assistance is expected Monday.

It is expected once the formal request is issued it will take about 48 hours to have the US contingent on the ground in Australia.

The deployment will not include firefighters to be used on the fire fronts.

"The positions will be mostly leadership and supervisory in nature," Smurthwaite said.

"We won't be sending firefighters at this point."

Bushfires in Victoria have killed at least 166 people with authorities expecting the toll to rise further as remains are found in more than 700 burnt-out homes.

News of Australia's worst bushfires is front page news in the US and has challenged US President Barack Obama's attempt to pass an $US827 billion ($A1.22 trillion) economic stimulus bill as the top story on TV news bulletins.

Two articles about the fires dominated the front page of the Los Angeles Times broadsheet newspaper, with one carrying the headline "Infernos are Australia's worst ever".

The tragedy has also sparked debate in the US about whether Australia's "stay and defend policy", which some US regions have contemplated introducing, should go ahead.