US President Donald Trump is preparing to sign a revised Executive Order temporarily barring the entry of people from certain Muslim-majority countries and halting the nation's refugee programme.

A White House official says plans to roll out the order are on track for tomorrow.

The new order has been in the works since shortly after a federal court blocked Trump's initial effort, but the Administration has repeatedly pushed back the signing.

Trump Administration Officials have said the new order aims to overcome the Legal Challenges to the first.

It's goal will be the same: keep would-be terrorists out the United States while the government reviews the vetting system for refugees and visa applicants from certain parts of the world.

The revised order is expected to remove Iraq from the list of countries whose citizens face a temporary US travel ban, following pressure from the Pentagon and State Department, which had urged the White House to reconsider, given Iraq's key role in fighting Isis (Islamic State).Trump's original orders temporarily blocked citizens of Iran, Iraq, Somalia, Sudan, Yemen, Syria and Libya from coming to the US and put on hold the US refugee programme.

The new order is also expected to make other changes, including no longer singling out Syrian refugees for an indefinite ban and making clear that all existing visas will be honoured.

Trump signed his original executive order in late January, sparking confusion and anger as travellers were detained at US airports and barred from boarding flights at foreign airports. The signing is expected to spark a new round of lawsuits and outrage.

Meanwhile, FBI Director James Comey asked the Justice Department to issue a statement refuting Trump's claim that President Barack Obama ordered a wiretap of Trump's phones before the election, but the department has not done so, according a US official.

Comey made the highly unusual request yesterday after Trump accused Obama on Twitter of having his 'wires tapped' in Trump Tower."

The revelation, first reported by the New York Times, underscores the fraught nature of the FBI's high-profile investigation into Russian meddling in the 2016 election. A key question fuelling the probe is whether Trump associates colluded with Russian officials to help Trump win.

The department declined to comment today, as did the FBI.