Over 130 US foreign policy experts have denounced President Donald Trump's revised travel ban, saying it undermines America's national security and interests as much as the original order barring travellers from some Muslim-majority countries and refugees.

“To Muslims ─ including those victimised by or fighting against ISIS (Islamic State) ─ it will send a message that reinforces the propaganda... that falsely claim the United States is at war with Islam,” read the letter by former government officials and experts.

“Welcoming Muslim refugees and travellers, by contrast, exposes the lies of terrorists and counters their warped vision,” added the document dated Friday.

Among the 134 signatories were some who served in either or both Republican and Democratic administrations were former senior diplomat Nicholas Burns, ex-National Security Council counter-terrorism director Richard Clarke and ex-undersecretary of defence Michele Flournoy.

Most served under Democratic presidents, including former secretary of state Madeleine Albright, former Homeland Security secretary Janet Napolitano, ex-national security adviser Susan Rice and ex-National Counterterrorism director Matthew Olsen.

Their comments echo those being made in court by US states claiming the modified measures discriminate against Muslims and are detrimental to US interests.

“Bans like those included in this order are harmful to US national security and beneath the dignity of our great nation,” the letter read.

The executive order “weakens this country's ability to provide global leadership and jeopardises our national security interests by failing to support the stability of our allies that are struggling to host large numbers of refugees,” it added.

The letter was also sent to Trump's Secretary of State Rex Tillerson, Defense Secretary James Mattis, Attorney General Jeff Sessions, Homeland Security chief John Kelly and Acting Director of National Intelligence Michael Dempsey.

The revised directive temporarily closes US borders to all refugees and citizens from six mainly-Muslim countries.

It denies US entry to all refugees for 120 days and halts for 90 days the granting of visas to nationals from Iran, Libya, Somalia, Sudan, Syria and Yemen.

The new order, unveiled Monday, is due to go into effect March 16 and replaces the previous Trump directive that was blocked in federal court.

The blocked order included an indefinite Syrian refugee travel ban and its blacklist of barred countries included Iraq.