A US federal judge has temporarily blocked President Donald Trump's new immigration ban, just hours before it was scheduled to be enforced on Thursday, a media report said.

In the Honolulu federal court, Judge Derrick Watson heard arguments on the state of Hawaii's request that a temporary restraining order be issued for the ban, and he ruled in favour of the motion on Wednesday afternoon.

This will prevent Trump's executive order from going into effect, media reported.

Several states are making efforts to halt the immigration ban, and on Wednesday presentations were made in federal courts in Hawaii, Maryland and Washington state as to why it should not be implemented.

Hawaii said that the order discriminates on the basis of nationality and would make it impossible for state residents to be visited by relatives from the six Muslim-majority countries included in the ban.

The state also argued that the travel ban would hurt the state's big tourism industry, as well as the ability to attract foreign students and recruit foreign workers.  

The new immigration ban would suspend for 120 days the US refugee acceptance program and bar for 90 days US entry to citizens from Iran, Somalia, Sudan, Syria, Yemen and Libya, taking the stance that they present a terrorism risk.

In contrast to Trump's first executive order signed on January 27 but later blocked in federal court, the new measure would exempt citizens of Iraq and those enjoying permanent US residence.

It also would eliminate the ongoing prohibition on entry for Syrian refugees and the exemption of Syrian Christians from the ban.

The executive order signed by the President also reduces from 110,000 to 50,000 the number of refugees the US would take in during 2017.

Hawaii filed the first lawsuit against the new immigration ban, and attorneys for the island state, the government of which is controlled by the Democrats.

It presented the suit in a Honolulu federal court asking for a temporary suspension of the measure Trump signed on March 6, although it was not scheduled to go into effect until March 16.

"Hawaii is special in that it has always been non-discriminatory in both its history and constitution," Hawaii Attorney General Douglas Chin said.

"Twenty per cent of the people are foreign-born, 100,000 are non-citizens and 20 per cent of the labour force is foreign-born."