Julian Leeser, who was the shadow attorney-general and opposition Indigenous Australians spokesman, quit the shadow cabinet to campaign for a 'yes' vote.
Mr Leeser remains adamant there are no personal hostilities in the party, saying it's an issue reasonable Australians can disagree on.
He will push to amend the prime minister's proposed wording but will support the voice being embedded in the constitution regardless.
"My view is this is something that could benefit Indigenous Australians," he told Nine's Today Show on Wednesday.
But he said he didn't think the government had the right model to ensure the best chance of success and would put amendments forward to make the model more flexible.
Deputy Liberal leader Sussan Ley said the party's frontbenchers would still be tied to the 'no' position, adding Mr Leeser's stance was unique due to his role in helping draft the foundations of the voice during the past decade.
Ms Ley said the party was unified behind its policy to oppose putting a voice in the constitution and instead focus on local, community-led efforts.
"The overwhelming view of our party room is the one that has been put forward right now by Peter Dutton and me," she told Seven's Sunrise.
"We believe in a local and regional voice because we want this to be, if you'd like, bottom-up, not top-down."
Ms Ley would not speculate on Mr Leeser's replacement.
Victorian conservative Michael Sukkar and NSW moderate Paul Fletcher have been touted for the shadow attorney-general portfolio.
Some Liberals would prefer the Indigenous Australians portfolio remained in the shadow cabinet.
Moderate Liberal MP Bridget Archer said Mr Leeser's stance as an "authentic conservative" would help other conservative-minded people vote 'yes'.
"This is an issue that should transcend the political cut and thrust," she told ABC TV.
"It's a moment of nation-building, unity, and I think we should be looking at how we can work together, how we can collaborate to make this successful."
Her leaders continue to argue a national voice will add another layer of bureaucracy and not adequately represent the voices of regional and rural communities.
Former Liberal Indigenous Australians minister Ken Wyatt, who was the first Aboriginal person elected to the House of Representatives, hit back at the opposition over claims the voice would be "elitist".
Mr Wyatt resigned from the Liberals last week after the party opted to oppose enshrining a national Indigenous voice in the constitution.
He said the voice would not be a "Canberra voice" but a grassroots body.
"It's about local community designing their regional voice and then the regional voice selecting people they want to represent them in Canberra," he told ABC 7.30.
"It's not a Canberra voice. It's not elite. It's people from the grassroots."
Mr Wyatt said it was critical to consultation on Indigenous issues that the voice was able to advise executive government before legislation was finalised and presented to parliament.
"This is not a detrimental process. It allows them to sit and put their position to government," he said.
"It's too late after a party room. It's too late after it's been tabled in parliament."
