“The Nationals were the most supportive of the idea of the Voice. They were better than the Liberals, better than some Labor Party people and this has been my experience for the last 10 years,” Pearson said on ABC Radio National.

Loading

“A number of MPs have told me that the reason they were open to the Voice was that they have Aboriginal people in their electorates. They see Aboriginal people every day. Aboriginal people enter the doors of the offices. So this is just a complete turnaround for the National Party.”

Pearson said Littleproud should hand the leadership over to Price, claiming he had completely capitulated to her views on the Voice before a referendum bill had even been put to parliament and a date set for the national vote.

The Nationals, he said, were “just a squalid little political party ... that is currently controlled by a kindergarten child”.

Pearson was equally scathing of Price, a Warlpiri-Celtic woman from Alice Springs, who he said was a “very compelling woman” who had been caught up in a “tragic redneck celebrity vortex” fuelled by right-wing think tanks.

“It involves right-wing people, particularly the Sydney and Melbourne-based right-wing think tanks. The Institute of Public Affairs and The Centre for Independent Studies – they’re the string-pullers. They’re the ones who have lined up behind Jacinta. This has been a campaign in the making over the last three years and their strategy was to find a blackfella to punch down on other blackfellas,” he said.

“The bullets are fashioned by the CIS and the IPA but ... it’s a black hand pulling the trigger.”

Price, who worked as the Indigenous program director at the CIS before entering parliament, condemned the remarks as “ugly” saying she was “no stranger to attacks from angry men who claim to speak on behalf of Aboriginal Australia”.

“We didn’t need a crystal ball to know that if you do not agree with the Voice to parliament, you will be called names, be accused of racism, bigotry and it will also be suggested that you are incapable of thinking for yourself,” she said in a statement.

Littleproud defended the party’s decision in a round of media interviews on Tuesday, where he said the party believed the Voice would do nothing to close the gap between Indigenous and non-Indigenous Australians. Speaking on ABC TV, he rejected the suggestion that the Nationals had imperilled the referendum.

“We’ve got a right to make a determination about the people we represent. No one should be shamed into any decision on this,” Littleproud said.

The move by the Nationals heightens the focus on the Liberal party room, which is yet to decide how it will approach the Voice.

Opposition Leader Peter Dutton on Tuesday told a joint party room meeting the Nationals had undertaken “significant internal processes” before stating their position and the Liberal Party respected that but was not itself ready to make a decision.

“There will be a discussion in the Liberal party room and the Coalition party room in due course. But we’re not there yet,” he said.

“Right now, the pressure needs to be on the prime minister to answer the most basic questions about the Indigenous Voice to parliament. Because when he is asked questions, he either doesn’t know the answers. Or, for the ones he does know, they simply give rise to more questions.

“There is a long time between now and the next election. We want more information, just like the rest of the country, before we can form a position.”

Former prime minister John Howard has counselled the Liberal Party against allowing MPs to have a free vote.

Pearson said Dutton was “a decent guy”, adding it would be “madness for the Liberal Party to not support this modest proposal”.

Speaking on ABC radio, Attorney-General Mark Dreyfus denied the government had played a role in the Nationals’ rejection of the Voice by not providing enough detail on the proposal.

Loading

“Not at all. The prime minister gave the clearest possible description of what’s needed. It’s a short question that’s going to be put to the Australian people and some short sentences to go into the Constitution,” Dreyfus said.

He said the Nationals’ decision, while “disappointing” was not a “death blow” for the upcoming referendum.

“I don’t think that that’s the end of the matter. We haven’t even started the campaign yet. We haven’t even got to a stage where people are familiar with what’s needed to change the Constitution.”

The 2017 Uluru Statement from the Heart, which was endorsed by hundreds of Indigenous leaders, called for the creation of a Voice to parliament that would provide advice on laws and policies affecting Aboriginal and Torres Strait Islanders.

Prime Minister Anthony Albanese told Indigenous leaders in September the government was “all in” and there was “not a day to waste” as they prepared the strategy for a “yes” vote in the referendum, which is slated to be held in the next financial year.

Cut through the noise of federal politics with news, views and expert analysis from Jacqueline Maley. Subscribers can sign up to our weekly Inside Politics newsletter here.