US President Donald Trump's revised travel ban targets the same seven countries listed in his original executive order and exempts green card holders and those who already have a visa to travel to the US, even if they have not used it yet.

According to a senior White House official, the order will target only those same seven Muslim-majority nations — Iran, Iraq, Syria, Somalia, Yemen, Sudan and Libya.

The President came up with a second order after federal courts held up his immigration and refugee ban. The order could come sometime this week, Fox News reported.

The official, who spoke on condition of anonymity to discuss the order, said green card holders and dual citizens of the US and any of those countries were exempted.

The new draft also no longer directs authorities to single out — and reject — Syrian refugees when processing new visa applications.

White House spokeswoman Sarah Huckabee Sanders said the version being circulated was a draft and the final version should be released soon.

Trump's original executive order triggered chaos at airports across the US, as travellers were detained when the order rapidly went into effect, US permanent residents known as green card holders among them.

Attorneys provided legal assistance to those held and protesters descended on the airports as news of the order's implementation spread.

The order temporarily suspended for 90 days all travel to the US for citizens of those seven countries.

The original order also called for Homeland Security and State Department officials, along with the director of national intelligence, to review what information the government needed to fully vet would-be visitors.

It asked them to come up with a list of countries that cannot or would not make the information available.

It said the government would give countries 60 days to start providing the information else citizens from those countries would be barred from travelling to the US.

Even if Syrian refugees are no longer automatically rejected under the new order, the pace of refugees entering the US from all countries is likely to slow significantly.

That is because even when the courts put Trump's original ban on hold, they left untouched the President's 50,000 per year refugee cap, a cut of more than half from the cap under the Obama administration.

The US has already taken in more than 35,000 refugees this year, leaving less than 15,000 spots before hitting Trump's cap.

This means that for the rest of this fiscal year, the number of refugees being let in per week will likely fall to a fraction of what it had been under the Obama administration's cap of 110,000.

The travel ban again came under attack when the ninth Circuit Court of Appeals in San Francisco refused to reinstate the ban, unanimously rejecting the administration's claim of presidential authority, questioning its motives and ability to survive legal challenges.

The pushback prompted Trump to tweet "SEE YOU IN COURT!" and he has since lashed out at the judicial branch, accusing it of issuing a politically motivated decision.

Homeland Security Secretary John Kelly, speaking at the Munich Security Conference about combating terrorism, said Trump was working on a "streamlined" version of the initial executive order.

Kelly said Trump's order was designed as a "temporary pause" to allow him to "see where our immigration and vetting system has gaps — and gaps it has — that could be exploited".

He said the Trump administration was surprised when US courts blocked the order and now "the President is contemplating releasing a tighter, more streamlined version" of the ban.

This time he will be able to "make sure that there's no one caught in the system of moving from overseas to our airports".

Kelly mentioned "seven nations" again on Saturday, leading to speculation they will all be included in Trump's next executive order.

The President's order sparked an immediate backlash and saw chaos and outrage, with travellers detained at airports, panicked families searching for relatives and protesters marching against the sweeping measure — parts of which were blocked by several federal courts.