Kemi Badenoch has said a Conservative government would scrap the "cliff edge" that mean parents in England lose out on childcare support when they earn more than £100,000 a year.
Speaking to the BBC's Laura Kuenssberg, the Conservative Party leader said: "What we want to see is that people who work harder don't get punished for doing so."
Under the current system, only families where no parent earns more than this threshold are eligible for government-funded or tax-free childcare.
The announcement comes as Conservative members gather for the party's annual conference in Birmingham.
Badenoch, who arrived in the city on Saturday, has vowed the party was new and different from the one that lost the 2024 general election.
The Conservatives - who have been polling behind Labour and Reform UK over the past year - are expected to use the four-day event to lay out more of its policy agenda ahead of the next general election.
Ahead of the conference, the Conservatives produced a 100-page essay setting out their principles including a "central" belief that business, rather than governments, create growth.
It argues that governments should create the conditions for growth, particularly through the tax system.
During her interview, Badenoch insisted the Tories would keep the state pension triple lock, which Prime Minister Andy Burnham has pledged to change if Labour wins the next election.
She said the policy, under which state pensions rise each year by the highest of inflation, average wages, or 2.5%, was "the right policy for pensioners".
She added: "What we don't want to see is people going after the elderly, chasing after vulnerable and disabled people, and then the extremely large cohort of people who can work, who are not working, are left alone."
The Conservatives have long called on the government to cut the growing welfare budget including by implementing tighter restrictions on claimants.
The party said its childcare announcement would be a "first step" in broader efforts to address issues in the tax system which damage incentives to work or invest.
This will be a theme of shadow chancellor Andrew Griffith's conference speech on Monday.
Since September 2025, working parents in England have been entitled to 30 hours of free childcare for children aged between nine months and four years old.
However, to qualify both parents must earn less than £100,000 a year, although all three and four-year-olds are eligible for 15 hours of free childcare, regardless of parental income.
The same £100,000 threshold, which was set by the Conservative government, applies to the government's tax-free childcare scheme.
For every £8 paid into an online childcare account, the government adds £2, up to £2,000 per child per year, which parents can then use to pay for childcare.
The Tories said that if they return to power they would remove the £100,000 threshold entirely so parents no longer lose childcare support when their income exceeds this level.
The threshold has been criticised by economists, who point out it can leave parents worse off overall even after a pay rise of tens of thousands of pounds.
In her interview with Kuenssberg, Badenoch added: "What we want to see is more people in work and not taking the wrong decisions or the wrong choices, and it doesn't matter whether they're earning £10,000 or £100,000 - what matters is that people are out there working".
Asked if this could result in someone who earns £1 million a year get free childcare under a Conservative government, the Tory leader responded: "It doesn't matter what you earn - we don't want you to be punished for working hard. What we're trying to do is grow our economy."
