Work and Pensions Secretary Liz Kendall defended the euthanasia bill, telling the BBC it was about "the right to choose".
She declined to criticize Justice Minister Shabana Mahmoud, who wrote to her constituents this weekend saying the proposed changes would create a "slippery slope to death on demand."
Kendall told Laura Kuenssberg on Sunday that she believed the bill would give people "power, choice and control" over their own deaths.
The bill, which would allow some terminally ill patients to access medically assisted dying, will be debated by MPs on Friday.
"I think you should have a choice," Kendall said in an interview with Laura Kuenssberg on Sunday.
"The point is not that this is for everyone."
Kendall, a long-time advocate for assisted dying, called the debate over the bill part of a "larger" national discussion as more people are "taking longer to die."
Her comments came as 29 faith leaders representing Christians, Muslims, Jews, Hindus and Sikhs signed an open letter warning that the Terminal Ill Adults (End of Life) Bill would lead to people being forced to end their lives to avoid placing a burden on families or the NHS. .
MPs will hold a free vote on the bill on Friday - introduction Author: Labor MP Kim Leadbeater - This means they can follow their conscience rather than the party's orders.
Public opinion shows a majority supports changing the law, The latest YouGov poll shows 73% of Britons hold this view Support euthanasia in principle.
Campaigning by both parties continues ahead of Friday's vote, which will be the first public show of support from lawmakers.
Former Labor prime minister Gordon Brown told BBC Radio 4's Sunday program that he wanted to see more debate on the issues.
"People want to know what the evidence is for the scale of the challenge," he said.
Brown, who has long criticized euthanasia and urged MPs to vote against the reform, said: "I view life as a gift - I think it's something to be cherished."
Mahmoud joins Health Minister Wes Streeting and Education Minister Bridget Philipson in saying they will vote against the bill.
Care Secretary Stephen Kinnock expressed support for the bill, while Prime Minister Sir Keir Starmer expressed support when MPs last debated the euthanasia proposal in 2015. This time, he said he would not pressure Labor MPs in any way.
Campaigners supporting the bill, including broadcaster Dame Esther Rantzen, argue terminally ill people should choose how they die to avoid unnecessary suffering.
Dame Esther, who revealed last year that she joined Dignitas after a terminal cancer diagnosis, called the new bill "fantastic".
Mahmoud said in the letter that the biggest risk of introducing euthanasia is "the pressure that older, vulnerable, sick or disabled people may put on themselves" to end their lives sooner.
She said she was "deeply concerned" about the legislation, not just for religious reasons but because it could create a "slippery slope to death on demand" and argued the government must "protect and preserve lives, not take them away" ".
Mahmoud added that scandals such as Hillsborough, tainted blood and Post Office Horizon "remind us that states and those who act on their behalf are not always benign".
Speaking to Sky News, Leadbeater said she had "no doubt whatsoever" that the bill she was introducing was the right one.
She said the current laws "failed", causing families to lose loved ones in "tragic circumstances" and allowing people to endure "painful deaths".
"By establishing a legal framework, we will improve the situation," she added.
The differences over the euthanasia bill do not fall neatly along party lines. Conservative shadow housing secretary Kevin Hollinrake told the BBC he planned to support the bill.
Hollinlake argued that he and others "wanted to make that choice" at the end of their lives and that he "believed the state was right to prevent them."
While acknowledging the concerns of other ministers, he said he was confident Parliament would maintain checks to protect the system.
Veteran broadcaster Jonathan Dimbleby has dismissed concerns about a "slippery slope" to assisted dying, citing the example of the US state of Oregon - which introduced similar laws 27 years ago but did not go further. Expand scope.
Appearing on the Laura Kuenssberg panel on Sunday, Dimbleby said he supported the bill and was influenced by the experience of his younger brother Nicholas, who died from motor neurone disease.
However, former Culture Secretary Nadine Dorris said she opposed the bill and called for more palliative care.
She said she was "eternally grateful" that her late husband changed his mind about suicide after being diagnosed with terminal cancer, allowing him to spend the "best four months" with his family before his death.
Meanwhile, broadcaster Piers Morgan told the panel he was conflicted but urged more funding for end-of-life care to ensure terminally ill patients die peacefully.