The deputy prime minister, Michael McCormack, has conceded Australia must take further action to combat the climate crisis and acknowledged that the bushfires ravaging New South Wales and South Australia have further shifted community sentiment on the issue.

But McCormack, who is acting prime minister while Scott Morrison returns from a much-maligned holiday in Hawaii, also linked the fires to other causes, including dry lightning strikes and self-combusting manure.

And he said former fire chiefs who had criticised the government were being funded by environmental campaigners.

At a press conference in Wagga Wagga on Saturday, the Nationals leader agreed the fires had impacted community sentiment on the climate emergency. Pressed on whether he agreed that “further action” was needed to tackle the climate crisis, he said: “I do, absolutely, I do agree entirely.”

Asked what more could be done, McCormack declined to be drawn further.

“We will have these discussions,” he said. “The important thing is we put the fires out. The important thing is we wrap our arms around people who’ve lost loved ones. The important thing is that we make sure we’ve got the proper resourcing and that we fully address these fires as they’re occurring.”

However, McCormack took a strident line against those calling for an end to coalmining and, while acknowledging it was a factor, also suggested there had been “a lot of hysteria about climate change” in the commentary around the fires.

“Climate change is not the only factor that has caused these fires. There has been dry lightning strikes, there has been self-combusting piles of manure, there has been a lot of arsonists out there causing fire.”

He added: “For those running around saying we should abandon coal right now, what are we going to do with our electricity over summer if we shut them all down today? Coal provides almost two-thirds of our energy needs.”

As for the coalition of former fire chiefs, including Greg Mullins, who are urging action on climate change and a shift to renewables, McCormack said without providing evidence that they were being funded by environmental author and scientist Tim Flannery.

The comments came as David Littleproud, the federal minister for natural disaster and emergency management, dodged questions about whether the government needed to do more on climate, saying only that Australia was committed to meeting the Paris targets.

In November, a new international report found Australia’s response to the climate crisis was one of the worst in the G20, resulting from a lack of policy, reliance on fossil fuels and rising emissions. This month, two former emergency services leaders called for a national summit to address how the country should prepare for and resource bushfire emergencies in a changed climate.

Fronting the media separately on Saturday, both McCormack and Littleproud were forced to defend Morrison’s trip to Hawaii. The prime minister is scheduled to arrive back in Australia on Saturday night, after saying he regretted taking the holiday while the nation was gripped by bushfires.

“No one could have envisaged what has transpired this week ... everyone is entitled to a holiday,” McCormack said.

Littleproud said: “The reality is the operational management of fires sits with the state governments and they do an exemplary job.

“We need to get out of their hair at times. There comes times when too many politicians are around.”

Littleproud also defended the resources offered to the state government-administered volunteer brigades as he confirmed about 30 Canadian firefighters would join their Australian counterparts on the ground on Sunday.

The deputy PM offered his condolences to the families Geoffrey Keaton and Andrew O’Dwyer, two NSW Rural Fire Service who were killed in the fires on Thursday night.

A second person was also confirmed dead in South Australia on Saturday afternoon.