US President Donald Trump has signed into law his sweeping domestic policy bill that includes tax breaks and spending cuts.

Trump signed the bill at the White House on Friday, following its passage in the Senate on Tuesday and at the House of Representatives on Thursday, both by a narrow margin.

The bill has raised concerns that the large-scale tax cuts could lead to financial decline. Even some ruling Republican lawmakers were opposed to the bill, but Trump successfully persuaded most of them to approve it.

He delivered a speech at the White House on Friday before the signing, "That's the largest tax cut in the history of our country," and stressed that America is expected to achieve economic growth "like a rocket ship."

The legislation extends personal tax cuts from his first term, and exempts taxes on tips and overtime pay for a certain period.

It also includes additional funding for border security. The enacted law features measures to reduce expenditures, such as abolishing and scaling down businesses to tackle climate change, and tightening the health insurance system for low-income people.

The US Congressional Budget Office estimates it will add about 3.4 trillion dollars to the US debt over the next decade.