Steven Mnuchin
US President Donald Trump (L) shakes hands with Steven Mnuchin after Mnuchin took the oath of office as the next US Treasury secretary in the Oval Office of the White House Mandel Ngan/AFP

US President Donald Trump is set to announce "the biggest tax cut in US history", according to Treasury Secretary Steven Mnuchin.

Speaking at an event hosted by political news website The Hill, Mnuchin said the president's budget would include a number of cuts, including a 15% tax rate for businesses and a simplification of personal taxes.

He said: "We had a very successful meeting last night and I think it is clear that the House, the Senate and the administration are all on the same page – that tax reform is a major priority to boost the economy, that the fundamental principles of making business tax competitive... we have a very uncompetitive system that's hindering the economy and jobs, we want to make business competitive and we want to simplify the personal tax system, lower taxes and create economic growth.

"So this is going to be the biggest tax cut and the largest tax reform in the history of our country and we are committed to seeing it through."

Further details of the tax plan are set to be released later on Wednesday (26 April), but Mnuchin did say there had been no firm decision on a border adjustment tax.

He told The Hill: "On the border adjust tax... there's many aspects we like and there are certain things were concerned about. What we've discussed with them is we don't think it works in its current form and we're going to continue to have discussions with them about revisions they will consider."

Mnuchin also the objective of the plan was the simplification of taxes, explaining people who could not afford to pay taxes would not be doing so.

However, Mnuchin insisted the tax cuts would not leave the government short of cash, telling the website: "We have the cash flow to manage the government. Matter of fact, we had one of the largest days ever of collecting tax receipts on April 18."