President Donald Trump will ask the United States Congress for dramatic cuts to many federal programmes as he seeks to bulk up defence spending, start building a wall on the border with Mexico and spend more money deporting illegal immigrants.

In a federal budget proposal with many losers, the Environmental Protection Agency and State Department stand out as targets for the biggest spending reductions. Funding would disappear altogether for 19 independent bodies that count on federal money for public broadcasting, the arts and regional issues from Alaska to Appalachia.

Trump's budget outline is a bare-bones plan covering just "discretionary" spending for the 2018 fiscal year starting on October 1. It is the first volley in what is expected to be an intense battle over spending in coming months in Congress, which holds the federal purse strings and seldom approves presidents' budget plans.

Congress, controlled by Trump's fellow Republicans, may reject some or many of his proposed cuts. Some of the proposed changes, which Democrats will broadly oppose, have been targeted for decades by conservative Republicans.


Moderate Republicans have already expressed unease with potential cuts to popular domestic programmes such as home-heating subsidies, clean-water projects and job training.

Trump is willing to discuss priorities, according to White House budget director Mick Mulvaney, a former South Carolina congressman who made a name for himself as a spending hawk before Trump plucked him for his Cabinet.

"The President wants to spend more money on defence, more money securing the border, more money enforcing the laws, and more money on school choice, without adding to the deficit," Mulvaney told a small group of reporters during a preview yesterday.

"If they have a different way to accomplish that, we are more than interested in talking to them," he said.

Trump wants to spend US$54 billion ($77b) more on defence, put a down payment on his border wall, and breathe life into a few other campaign promises. His initial budget outline does not incorporate his promise to pour US$1 trillion into roads, bridges, airports and other infrastructure projects. The White House has said the infrastructure plan is still to come.

The defence increases are matched by cuts to other programmes so as to not increase the US$488b federal deficit. Mulvaney acknowledged the proposal was likely to result in significant cuts to the federal workforce.

"You can't drain the swamp and leave all the people in it," Mulvaney said.

White House officials looked at Trump's campaign speeches and "America First" pledges as they crunched the numbers, Mulvaney said. "We turned those policies into numbers," he said, explaining how the document mirrored pledges to spend more on the US nuclear arsenal, veterans' healthcare, the FBI, and Justice Department efforts to fight drug dealers and violent crime.

The Department of Homeland Security would get a 6.8 per cent increase, with more money for extra staff needed to catch, detain and deport illegal immigrants.

Trump wants Congress to shell out US$1.5b for the border wall in the current fiscal year - enough for pilot projects to determine the best way to build it - and a further US$2.6b in fiscal 2018, Mulvaney said.

Trump asked Congress to slash the EPA by US$2.6b or more than 31 per cent, and the State Department by more than 28 per cent or US$10.9b.

Mulvaney said the "core functions" of those agencies would be preserved. Hit hard would be foreign aid, grants to multilateral development agencies such as the World Bank, and climate change programmes at the United Nations.

Trump wants to get rid of more than 50 EPA programmes, end funding for former Democratic President Barack Obama's signature Clean Power Plan aimed at reducing carbon dioxide emissions, and cut renewable energy research programmes at the Energy Department.

Regional programmes to clean up the Great Lakes and Chesapeake Bay would be sent to the chopping block.

Community development grants at the Housing Department - around since 1974 - were cut in Trump's budget, along with more than 20 Education Department programmes, anti-poverty grants, a programme that helps poor people pay their energy bills and a programme that helps low-income seniors find work.