Washington DC - President Donald Trump rallied Republicans on Capitol Hill Tuesday to back his so-called "Big Beautiful Bill" that will expand tax cuts for the rich while slashing health care for millions of Americans.

Sharp divisions in the party have slowed the progress through Congress of Trump's budget bill, which pairs an extension of the billionaire's signature tax cuts – mainly favoring the wealthy – from his first term with a series of savings.

But conservatives are angling for much deeper spending cuts to tackle the ballooning deficit, while moderates say the savings would mean millions of the poorest Americans lose health coverage under the Medicaid program.

As he was greeted by Republican House Speaker Mike Johnson, Trump said that there were "one or two grandstanders" blocking the bill but that he was confident of a deal.

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He warned that without the bill the US would face huge tax increases.

"I think we're going to have a very good discussion. There are one or two points that some people feel strongly about, but maybe not so strong," Trump told reporters as he went in to meet lawmakers.

Trump has been eager to present the bill as a significant legislative accomplishment early in his second term, after a frenzied first few months during which he has governed largely through presidential orders.

Independent congressional analysts calculate that the mega-bill's tax provisions would add more than $4.8 trillion over the coming decade.

Trump insisted that he was "not touching" Medicaid but just cutting "waste, fraud and abuse" – the slogan of the administration's dismantling of government agencies and programs led by tech tycoon Elon Musk.

Instead, the bill would add new restrictions on the Medicaid program that helps provide health insurance for more than 70 million lower-income Americans.

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They would include even more burdensome work requirements for those receiving assistance and cutting it for undocumented migrants.

The policy change would result in more than 10 million people losing coverage under the program, according to estimates by the independent Congressional Budget Office.

Asked whether he could guarantee voters would not lose their health insurance under the legislation, Trump on Tuesday again said they would not.

The bill – formally known as the "One Big Beautiful Bill" – cleared a key hurdle on Sunday when it finally progressed out of the House Budget Committee, but would face even bigger challenges in the Senate, where Republicans are demanding major changes.