The seven families are the first to arrive in Australia from Central American as refugees under a deal struck by Prime Minster Malcolm Turnbull and then US president Barack Obama last year.

Although few other details are available about the 30 individuals - in part to preserve their safety - Fairfax Media understands the main applicants and their family had been living in hiding in El Salvador and faced gang-related intimidation and violence before being transferred to Costa Rica.

The UNHCR, International Organisation for Migration and US government have established a "Protection Transfer Arrangement" in Costa Rica and, after referral by the UNHCR, the Australian government assessed the 30 people and granted them humanitarian visas.

Immigration Minister Peter Dutton - who has been criticised by asylum seekers, the UN and human rights groups for Australia's offshore detention system and a hardline approach to people attempting to arrive by boat - said the Turnbull government had "restored integrity to our refugee and humanitarian program".

As a result, "the dividend of this is that we can provide the most vulnerable in the world the new start to their life that they deserve. This intake provides deserving people with an opportunity to start a new life in our country. It's a Christmas gift they could never have imagined possible a few years ago," he said.

"Australia remains one of the top three countries for resettlement of refugees. The 2016-17 offshore humanitarian program was the largest in over 30 years."

According to the UNHCR, the number of people fleeing gang violence in countries such as El Salvador, Guatemala and Honduras has skyrocketed in recent years. Most head to Mexico or Costa Rica and then on to the United States.

As part of the Turnbull-Obama deal, the US agreed to take as many as 1250 asylum seekers who were sent to Nauru or Manus Island by the Australian government; after sharply criticising the "dumb deal", US President Donald Trump eventually backed down and agreed to honour the agreement struck by his predecessor.

So far, an initial group of 54 refugees from Manus Island and Nauru were accepted by the US last September and a second group of about 200 men, women and children are expected to arrive in America in January.

Australia will accept 18,750 refugees in 2018-19, and an additional 12,000 people fleeing from the war in Syria and Iraq.