Though expected to be approved, Sunak’s plan to impose some of the world’s strictest anti-smoking rules has angered some members of his governing Conservative Party, including former prime ministers Liz Truss and Boris Johnson, who say the state should not interfere in how people live their lives.
Lawmakers will be given a so-called free vote on the bill, meaning they do not have to vote along party lines. A similar law in New Zealand was scrapped this year by the new coalition government before the legislation went into force.
A large Conservative rebellion would be another blow for Sunak, who has already faced criticism in his party over issues ranging from climate change to defence policy.
The legislation is one of Sunak’s flagship policies before an election later this year which opinion polls suggest the opposition Labour Party will win.
The Tobacco and Vapes Bill aims to prevent children born since 2009 from ever being able to legally buy tobacco, rather than criminalising the habit.
Sunak has said it will tackle “the single biggest entirely preventable cause of ill-health, disability and death”.
There is strong support for the move from medical and healthcare experts and charities, who say smoking causes 80,000 deaths every year plus many more smoking-related illnesses.
But Conservative lawmaker Simon Clarke told BBC radio that a ban could be counterproductive.
“I think, it actually risks making smoking cooler. It certainly risks creating a black market and it also risks creating a unmanageable challenge for the authorities,” he said.
Despite such criticism, the legislation is widely expected to pass, with Labour suggesting it will support the measure. If it is approved on Tuesday (local time), the bill will progress to the next stage in parliament.