Nationals frontbencher Andrew Gee has broken ranks with his colleagues, arguing it is "absurd" for his party to expect him to change his stance on supporting an Indigenous Voice to Parliament.
On Monday, the junior Coalition partner announced it would oppose a constitutionally enshrined body, describing it as a divisive policy that would do little to improving the lives of First Nations people.
Mr Gee represents the regional New South Wales electorate of Calare, and was not present at the party room meeting on Monday where the position was settled.
He insisted his support for the Voice was clear and unwavering.
"I have a very long-standing view on it, and so I'm not going to change it," Mr Gee said.
"If the expectation was from anyone that I was just going to fall into line on it — I mean, it's just never going to happen.
"It's absurd to think that that that is going to be the case."
Mr Gee maintained he had outlined his position clearly, although he did not get a chance to speak directly with party leader David Littleproud before the announcement was made.
"David respects all views and I'm not expecting him to be upset about this," he said.
He committed to crossing the floor and voting with the government over the issue.
"While there is more detail certainly required, without a doubt, we have to keep working at it in good spirit and with open heart," he said.
"In time, it can lead to positive outcomes — that's the whole point of this, as well as being a really important part of the reconciliation process, which is unfinished in Australia."
Former minister critical of Nationals
Former minister for Indigenous Australians Ken Wyatt joined the criticism of the Nationals, arguing he had presented details to cabinet as to how a Voice to Parliament would work.
"People who were ministers at the time would be fully aware of this report," he said.
"What is obvious with the National party is they have not read the report and have not given an Aboriginal Voice to Parliament an opportunity to be aired and to be listened to and be implemented."
Mr Wyatt, who lost the West Australian seat of Hasluck at the last election, said opponents of the Voice clamouring for more detail of how it would operate were guilty of "laziness".
"I think it's being used as an excuse," he said.
"And to my mind, it offers up a level of immaturity around a very complex issue."