The Trump administration is proposing a major overhaul of the US State Department that would involve axing a war crimes office and shifting the focus of staff looking at migration and refugees.

Secretary of State Marco Rubio said the restructuring was designed to get rid of offices that are "misaligned with America's core national interests".

The planned cuts at the department include the Office of Global Criminal Justice, which helps set policy on the US response to war crimes and genocide.

A State Department spokesperson denied that Elon Musk's Department of Government Efficiency (Doge) was behind the proposal.

The proposal would eliminate around 130 of 732 domestic offices and scrap 700 jobs as part of what Rubio presented as a major restructuring, which he said would cut out "radical ideologues" and "bureaucratic infighters".

Rubio said the State Department cost and size had "ballooned" in the past 15 years.

"The problem is not lack of money, or even dedicated talent, but rather a system where everything takes too much time, costs too much money, involves too many individuals, and all too often ends up failing the American people," Rubio said on Tuesday.

Another office whose functions look set to be radically changed is one which deals with refugees and migration.

The proposed overhaul does not go as far as some US media reported in the run up to the announcement. It does not impact US embassies and missions overseas, and some functions of offices being cut look set to be moved into other offices that will be retained.

But the planned changes are significant and echo the kind of language the White House and Musk, who has been tasked with slashing the size and spending of the government, have been using since Trump took office.

They have said the US government is beholden to radically liberal civil servants who stifle their conservative agenda, a position vehemently rejected by critics who have condemned the cuts.

Jeanne Shaheen, the leading Democrat on the Senate foreign relations committee, said she would scrutinise the proposed reforms, adding that the Trump administration had engaged in a "slash and burn" campaign of the federal government.

"The lack of transparency to date only underscores that they know this process has been deeply flawed," she said.

When asked whether Doge was involved in the proposal, State Department spokeswoman Tammy Bruce said: "Doge was not in charge of this, but this is the result of what we've learned."

Musk has already overseen the scrapping of the foreign assistance agency USAID, which has had most of its functions axed.