Premier Blaine Higgs says he will give his entire caucus, including his cabinet ministers, a free vote on controversial legislation to tighten vaccination requirements for schoolchildren.

Higgs told reporters all 21 Progressive Conservative MLAs will be able to vote as they choose on Bill 39, which would require vaccinations for all schoolchildren unless they have valid medical exemptions.

"If we bring it in as a free vote, I think we have to exercise that as a free vote, and say that this is an item that everyone votes their conscience on," Higgs said.

The bill, introduced by Education Minister Dominic Cardy, would eliminate existing religious and philosophical exemptions for unvaccinated children.

A committee of MLAs held three days of hearings on the bill in August and some Tories acknowledged they were unsure how they'd vote on it.

Sussex-Fundy-St. Martins PC MLA Bruce Northrup said he was struggling with the idea of "telling my friends what they should be doing with their children. … I've been an MLA for 13 years and this is probably the biggest struggle I've had, personally."

Justice Minister Andrea Anderson-Mason also refused to commit to voting for the bill, despite being a member of the PC cabinet that approved the legislation for tabling in the legislature.

After the hearings, Cardy said that under the Westminster model of government, any minister who opposes a bill approved by cabinet is obligated to resign if they plan to vote against it.

"That might be his view, and I can understand that particular comment," Higgs said of Cardy's remarks.

But the premier said the legislature's vote to send the bill to public hearings at a legislative committee opened the door to the bill being amended.

He said after the committee issues its report on Bill 39, the PC caucus will discuss how to proceed.

"Some will agree and some won't, but we move on with the decision."

Education Minister Dominic Cardy has likened unvaccinated students to guns in schools. (CBC)

Cardy also criticized MLAs on the committee for not asking tougher questions of anti-vaccination activists.

Asked about those comments, Higgs said he encourages his ministers and MLAs to express their views but "it's not helpful when we get sparring at each other in the media, in social media."

Liberal Leader Kevin Vickers will also allow a free vote by his 20 MLAs in the legislature.

Cardy told the committee last month it's vital to maintain a 95 percent vaccination rate among schoolchildren to create "herd immunity." That prevents the spread of diseases to a small number of children who can't be vaccinated for legitimate medical reasons.

But he acknowledged that there are 18,000 incomplete vaccination records in six school districts. Some MLAs said this raises questions about whether tougher legislation is needed.

Higgs said everyone in his caucus "feels it's the right thing to do," but "the areas of debate are around the constitutionality of it, and in the case of our current statistics, where are we, and what are the thresholds of where we're at risk?"

Some opponents of Bill 39 told the committee that the legislation would violate their rights. Cardy said there has been no Supreme Court of Canada case testing whether the need to protect public health would outweigh those rights.