The US Supreme Court has allowed President Donald Trump's signature travel ban to come into full effect even as challenges against it continue in the lower courts.

This latest edition of the travel ban stops residents of Chad, Iran, Libya, Somalia, Syria, Yemen and North Korea from entering the United States.

Earlier court rulings said that the ban excluded people with "bona fide" relationships with someone in the United States.

Two appeals courts, one in San Francisco and one in Richmond, Virginia, are hearing argument on the ban's legality this week.

Two supreme court justices, Ruth Bader Ginsburg and Sonia Sotomayor would both have kept the halt on the ban ordered by the lower courts.

The Supreme Court said it had considered the case "on an expedited basis" and expected the appeals courts to render their decisions" with appropriate dispatch".

This current version is the third attempt at a travel ban by the Trump administration, having twice been shot down by the courts.

Previous attempts were stopped in US courts owing to perceived religious discrimination, partly due to previous comments by Donald Trump himself.

The recent furore after he retweeted dubious anti-Muslim videos by a British far-right group suggested that they could end up being used against him in challenges to his own travel ban.

While previous iterations had only included Muslim-majority countries, the latest one also included North Korea.

After rising tensions due to the country's continuing nuclear ambitions, the US has sought to further economically isolate North Korea internationally with stringent sanctions against the country and those who do business with the country.