Sir Keir Starmer has said that Labour MPs must “make their own mind up” on whether to vote in favour of legalising assisted dying.
The Terminally Ill Adults (End of Life) Bill, from Labour MP Kim Leadbeater, is due to be published on Tuesday and is likely to run to more than 40 pages.
Ms Leadbeater has said the draft assisted dying laws will feature the “strictest protections” against coercion anywhere in the world.
Sir Keir was asked if he was going to vote in favour of the legislation and whether he had any concerns about potential coercion or issues raised by disability charities.
The Prime Minister said: “Look, it’s going to be a free vote and I mean that. It will be for every MP to decide for themselves how they want to vote.
“I’m not going to be putting any pressure whatsoever on Labour MPs. They will make their own mind up, as I will be.
“Obviously a lot will depend on the detail and we need to get the balance right but I’ve always argued there will need to be proper safeguards in place.”
Sir Keir has previously supported assisted dying, but said that the Government will remain neutral on the issue.
He has been careful not to express a view since the Bill was introduced.
Health Secretary Wes Streeting voiced his fears about coercion when he told ITV’s Good Morning Britain last month he worries “about those people who think they’ve almost got a duty to die to relieve the burden on their loved ones”, and Archbishop of Canterbury Justin Welby told the BBC assisted dying “has led to a slippery slope” elsewhere in the world.