Barnaby Joyce is feeling free to speak his mind now he is a candidate and not the deputy prime minister.

Key points: Ex-deputy PM wants a referendum to decide on all constitutional changes including the part the High Court used to kick him out

Ex-deputy PM wants a referendum to decide on all constitutional changes including the part the High Court used to kick him out Joyce says New England voters don't think the rules in section 44, and consequently the High Court's decision, are logical

Joyce says New England voters don't think the rules in section 44, and consequently the High Court's decision, are logical Former Nationals leader defends his replacement Nigel Scullion, says he could have acted as PM while Turnbull was away

"I am Barnaby," he has declared, making a radical call for a long list of potential changes to the constitution to be put to a referendum at the next election.

That list would include a question about overhauling section 44 of the constitution, which saw him knocked out of Parliament.

Mr Joyce is campaigning to win back his seat of New England at a by-election called after the High Court ruled he was ineligible to stay in Parliament because of his dual New Zealand citizenship.

He said voters did not accept what had happened.

"Everywhere I go, the overwhelming sentiment in the New England is people are saying: 'How could you be born in the Tamworth Base Hospital, where your great grandmother was born in Tamworth, where your great grandfather was born in Glen Innes, where you served in the Australian Army Reserves and somehow you are not an Australian? I mean, does that work?'" Mr Joyce told RN.

"To be quite frank I have a hard time trying to explain that to them."

Labor frontbencher Jason Clare said trying to change the constitution to overcome Mr Joyce's citizenship problem would backfire.

"If politicians put a proposal to the Australian people that just made it easier for politicians to become members of parliament, I think the Australian people would rightly tell us to get stuffed," Mr Clare said.

Acting Labor leader Tanya Plibersek called Mr Joyce's plan a ridiculous proposition.

"It is much easier to obey the law than to change it in the case of large constitutional changes like this," she said.

The loss of Mr Joyce as deputy prime minister and Nationals senator Fiona Nash, who was also a Cabinet minister, created a drama within the Coalition that resulted in Malcolm Turnbull taking a day to decide who should be acting prime minister when he travels overseas.

Some Liberals are furious with the Nationals for the citizenship crisis and for then arguing that their acting leader Nigel Scullion should have been chosen as acting PM instead of Foreign Minister Julie Bishop.

"I just get annoyed, because it is always off the record [when people] start making comments about the National Party," Mr Joyce said.

In comments that may further inflame the intra-Coalition tensions, Mr Joyce argued that the Nationals were responsible for last year's election victory because they held all their seats and won an extra one while the Liberals went backwards.

The delay in naming an acting prime minister reinforced the appearance of chaos in the Government after the High Court's ruling.

But Mr Joyce has defended making a push for Senator Scullion rather than Ms Bishop.

"Nigel Scullion sits in my part, of course I am going to spruik for his credentials. What is wrong with backing someone in from your own team? Isn't that what you are supposed to do?" he said.