Prime Minister Scott Morrison has defended a video posted on social media detailing the government's bushfire response after it was labelled "shameless" and a breach of political advertising rules.

The much-criticised video, authorised by Mr Morrison and posted on Saturday, describes how the government is deploying up to 3000 army reservists in response to the ongoing crisis.

The video includes details of defence ships and aircraft that have been deployed along with funding allocated for more firefighting craft, volunteer firefighters and those who lost homes or incomes.

The Liberal Party also posted details of the government response on its social media channels, following Mr Morrison's announcement of the stepped-up measures earlier on Saturday.

Mr Morrison took to Twitter to defend the video late yesterday, saying it was a legal requirement in Australia to include an authorisation on all video messages used by MPs on social media.

"The video message simply communicates the Government's policy decisions and the actions the Government is undertaking to the public," he posted.

"The same practice is rightly employed by the Leader of the Opposition and the Labor Party. This is required and standard practice in Australia."

On Sunday morning the prime minister faced fresh criticism for not alerting fire authorities before his actual announcement of the defence deployment .

NSW Rural Fire Service Commissioner Shane Fitzsimmons said he was disappointed about the lack of notice and expressed concern to the prime minister's office.

"All I can say I wasn't aware of it," Mr Fitzsimmons told the TODAY Show.

"I found out about it via the media reports. We then spent a fair bit of time with the military liaison trying to understand the details were. We are still working through that and made progress last night."

British broadcaster Piers Morgan slammed the video as a "self-promotional commercial with cheesy elevator music".

"This is one of the most tone-deaf things I've ever seen a country's leader put out during a crisis. Shameless & shameful," he posted on Twitter.

The Australia Defence Association, a non-partisan public-interest watchdog, accused the government of breaching rules around political advertising.

"Party-political advertising milking ADF support to civil agencies fighting bushfires is a clear breach of the (reciprocal) non-partisanship convention applying to both the ADF & Ministers/MPs," the association tweeted.

Former prime minister Kevin Rudd also expressed outrage.

"On a day we have catastrophic fire conditions, in the midst of a genuine national crisis, Morrison, the marketing guy, does what? He releases a Liberal Party ad! He is no longer fit to hold the high office of prime minister," Mr Rudd tweeted.

The prime minister has faced criticism for not acting sooner to bolster the nation's firefighting capabilities, and for going on holiday to Hawaii during the crisis.

Mr Morrison said the federal government had respected the states' bushfire response for months before it became clear a national response was needed.

"We have spent three to four months operating under … the national set of arrangements the states and territories recommended and wanted," he told News Corp.

"Now I have said 'we are doing this'."

The prime minister also said he would continue to offer hugs to those who wanted them even if he was abused.

"Whoever wants one, whoever wants to shake the hand, whoever wants to flip the bird … bring it on," he said.

"People are in different frames (of mind), some people need a hug. You just roll with it, you've still got to go out there … people do want to see you."

Mr Morrison was heckled last week in the NSW town of Cobargo, where a father and son died in a bushfire.