US President Donald Trump has said he is seeking a "historic increase" in military spending of more than 9 per cent to be funded by cuts elsewhere in government.

Key points: Donald Trump says the budget will be about public safety and national security

Donald Trump says the budget will be about public safety and national security President's budget plan needs to be approved by Congress

President's budget plan needs to be approved by Congress US already spends about $759 billion annually on defence

Mr Trump will seek to boost Pentagon spending by $US54 billion ($70 billion) in his first budget proposal and slash the same amount from non-defence spending, including a large reduction in foreign aid, a White House budget official said.

The President does not have the final say on federal spending.

His plan to ramp up military spending is part of a budget proposal to Congress, which, while it is controlled by his fellow Republicans, will not necessarily follow his plans.

Mr Trump told state governors at the White House that his budget plan included a "historic increase in defence spending to rebuild the depleted military of the United States of America".

"This is a landmark event and message to the world in these dangerous times, of American strength, security and resolve," he said.

"We must ensure that our courageous servicemen and women have the tools they need to deter war and when called upon to fight in our name, only do one thing: win."

Sorry, this video has expired Beverley O'Connor speaks to Todd Harrison from the Centre for Strategic and International Studies

Officials familiar with Mr Trump's proposal said the planned defence spending increase would be financed partly by cuts to the State Department, Environmental Protection Agency and other non-defence programs.

"We're going to do more with less and make the government lean and accountable to the people," Mr Trump said.

Such a hike would be unusual given that the United States is not engaged in a major war, although its special forces and Air Force are active against Islamic State militants in Iraq and Syria.

An official familiar with the proposal said Mr Trump's request for the Pentagon included more money for shipbuilding, military aircraft and establishing "a more robust presence in key international waterways and chokepoints" such as the Strait of Hormuz and South China Sea.

'Comparable to the largest peacetime build-ups'

The US already spends about $760 billion annually on defence. ( ABC News: Giulio Saggin, file photo )

That could put the United States at odds with Iran and China.

The US military is already the world's most powerful fighting force and the United States spends far more than any other country on defence.

Defence spending in the most recent fiscal year was $US584 billion ($759 billion), according to the Congressional Budget Office, so Mr Trump's planned $US54 billion ($70 billion) increase would be a rise of 9.2 per cent.

But White House budget director Mick Mulvaney said the plan would bring the Pentagon's budget to $US603 ($785 billion) in total, just 3 per cent more than the previous year's $US584 billion ($759 billion) total.

The rise would be slightly higher than the country's current 2.5 per cent rate of inflation.

"President Trump intends to submit a defence budget that is a mere 3 per cent above President (Barack) Obama's defence budget, which has left our military underfunded, undersized, and unready to confront threats to our national security," John McCain, the Republican chairman of the Senate Armed Services Committee, said in a statement.

In a speech to conservative activists on Friday, Mr Trump promised "one of the greatest military build-ups in American history".

Mark Cancian, an adviser with the Centre for Strategic and International Studies think tank, said Mr Trump's plan was in line with the kind of military spending seen before the Iraq war.

"This is certainly comparable to the largest peacetime build-ups, which would be 2003," Mr Cancian said.

How US miltary spending compares to the world The proposed boost of $US54 billion ($70 billion) is more than double Australia's annual defence budget of $32.4 billion

The proposed boost of $US54 billion ($70 billion) is more than double Australia's annual defence budget of $32.4 billion According to a report from the Institute of Stratefic Studies, the top 14 defence budgets under the US combined (including Australia) was $US664 billion compared to the total US budget of $US598 billion

According to a report from the Institute of Stratefic Studies, the top 14 defence budgets under the US combined (including Australia) was $US664 billion compared to the total US budget of $US598 billion The rest of the world spent a total of $US317 billion on defence

The rest of the world spent a total of $US317 billion on defence The top five countries under the US were China ($US146 billion), Saudi Arabia ($US82 billion), Russia ($US66 billion) and the UK ($US56 billion)



A former Defence Department and Office of Management and Budget employee, Mr Cancian cautioned that the proposal was far from being a budget.

"This is just giving everyone the top line," he said.

Nancy Pelosi, the top Democrat in the House of Representatives, said Mr Trump's plan to slash funding for federal agencies to free up money for the Pentagon showed he was not putting American working families first.

"A $US54 billion cut will do far-reaching and long-lasting damage to our ability to meet the needs of the American people and win the jobs of the future," Ms Pelosi said.

"The President is surrendering America's leadership in innovation, education, science and clean energy."

State Department likely to take major hit

The White House is sending Mr Trump's proposal to federal departments this week as he gears up for budget negotiations with Congress that often take months to play out.

A second official said the State Department's budget could be cut by as much as 30 per cent, which would force a major restructuring of the department and elimination of programs.

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The United States spends about $US50 billion ($65 billion) annually on the State Department and foreign assistance.

More than 120 retired US generals and admirals urged Congress on Monday to fully fund US diplomacy and foreign aid, saying that "elevating and strengthening diplomacy and development alongside defence are critical to keeping America safe".

Mr Trump also said he would talk about his plans for infrastructure spending in a speech to Congress on Tuesday.

"We're going to start spending on infrastructure big," he said.

Treasury Secretary Steven Mnuchin, speaking on Fox News on Sunday, said Mr Trump's budget would not seek cuts in federal social programs such as Social Security and Medicare.

Reuters