SYDNEY: Australian dual-nationals will not be affected by US President Donald Trump's executive order blocking visitors from seven Muslim-majority nations, Australian Prime Minister Malcolm Turnbull said on Tuesday.

Trump's executive order placed a 90-day bar on citizens from Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen from entering the United States, igniting chaotic scenes over the weekend as border and customs officials struggled to put the order into practice.

"Australian passport holders will be able to travel to the United States in the same way they were able to prior to the executive order," said Turnbull.

"Regardless of their place of birth or whether they are dual-nationals or they hold another passport, they will be welcome in the United States."

Australia joins Canada and the United Kingdom in winning exemptions for their dual citizens, while New Zealand Prime Minister Bill English said on Tuesday he expected to secure a similar arrangement.

Trump's executive order also placed a 120-day hold on allowing refugees into the country and an indefinite ban on refugees from Syria.

Despite the restrictions on refugees, Trump on Sunday told Turnbull the US would honor its agreement to resettle an unspecified number of refugees held in Australian processing centers on remote Pacific islands in Papua New Guinea and Nauru.

Under Australian rules, anyone intercepted while trying to reach the country by boat is sent for processing to camps in the tiny nation of Nauru and at Manus Island, in PNG. They are never eligible to be resettled in Australia.

But questions remain over how many refugees will be resettled in the United States, with humanitarian organizations fearing that many of the 1,100 refugees in offshore detention will not be accepted, leaving them in limbo.

"The people on Nauru and Manus Island have suffered enough at the hands of Australia's deliberately cruel policies," Graham Thom, refugee coordinator for Amnesty International Australia, said in a statement.

"The vague state of the arrangement and lack of information being provided to them in the current turmoil is deeply distressing."