Immigration officials have been told to open the door to more refugees from South America in a formal directive that is likely to change the make-up of the annual 18,750 humanitarian intake from next month.

Immigration Minister David Coleman prepared the plan in March and confirmed it following the May election, but the number of refugees accepted is unlikely to be known for more than a year.

More than half the refugees who come to Australia each year are from Iraq and Syria, an arrangement that is not expected to change as a result of the minister's decision.

Australia accepted 4630 refugees from Iraq and 3227 from Syria in the year to June 2018, with another 2043 from Myanmar, 1355 from the Democratic Republic of the Congo and 1130 from Afghanistan.

This followed a one-off intake of 12,000 refugees from Iraq and Syria, announced by former prime minister Tony Abbott in 2015.

While there is no public target on the intake from South America, it is expected to amount to several hundred people and could mean Venezuela joins the list of top 10 countries of birth for humanitarian visas in the year ahead.

This is a significant departure from decades of practice in which almost all the humanitarian intake came from Africa, Asia and the Middle East.

The justification for the new direction is the scale of the crisis in Venezuela, with an estimated 3 million of the country's citizens fleeing civil unrest under socialist president Nicolas Maduro and his predecessor Hugo Chvez.

The United Nations High Commission for Refugees has called this "the largest exodus in the recent history of Latin America" and warned of a 4000 per cent increase in Venezuelans seeking refugee status since 2014.

Venezuela has suffered from hyperinflation and fuel shortages since a contested election last year in which Mr Maduro claimed victory against opponent Juan Guaid, who declared the election a sham.

Foreign Minister Marise Payne recognised Mr Guaid's claims in January, saying he should assume the position of interim president.

Mr Coleman's move follows the government's decision in 2016 to accept refugees from Central America, an offer made by former prime minister Malcolm Turnbull in negotiations with former US president Barack Obama.

The Central American arrangement was linked to the US offer to accept hundreds of asylum seekers from Manus Island and Nauru, a deal Mr Turnbull confirmed with US President Donald Trump in a stormy phone conversation later leaked to the media.

While Mr Turnbull announced the permanent increase in the humanitarian intake from 13,750 to 18,750 in September 2016, there was no significant increase in the refugee intake from Central America.

No Latin American country has been named on the list of the top 10 countries of birth for the Australian humanitarian intake in the years since the 2016 agreement. In the year to June 2017, the 10th nation on the list was Somalia with 162 refugees. The 10th nation on the list last year was Tibet with 200.

Home Affairs Minister Peter Dutton told the ABC's Insiders program last Sunday that two Rwandans had been accepted by Australia from the US but suggested no others had come under the US arrangement.

"We don't have plans to bring any others from America at this stage," he said.