Home Affairs Minister Peter Dutton says he does not know whether people charged with serious offences have arrived in Australia under the so-called medevac bill.

Key points: After the medevac bill passed, the Coalition warned of "a flood of about 300 immediate transfers" to Australia

After the medevac bill passed, the Coalition warned of "a flood of about 300 immediate transfers" to Australia Mr Dutton told Insiders that "only just over 30" people had been transferred so far

Mr Dutton told Insiders that "only just over 30" people had been transferred so far The Home Affairs Minister said 531 people had left for the US under the refugee resettlement deal

The law, passed earlier this year, makes it easier for refugees and asylum seekers on Manus Island and Nauru to seek medical treatment in Australia.

The Opposition and crossbenchers approved the legislation in an historic defeat for the Government.

The Coalition had warned the move would see "a flood of about 300 immediate transfers" to Australia, including paedophiles, rapists or murderers.

But Mr Dutton told Insiders "only just over 30" people had so far been transferred under the legislation.

Asked whether people charged with serious offences had travelled to Australia, he said: "I don't know the answer to that question in terms of the concerns that we have about individuals.

"I think we'll wait and see what happens without sounding alarm bells.

"We don't bring anyone to our country where we can't mitigate the risk."

Mr Dutton said none of those transferred had been taken to Christmas Island.

Prime Minister Scott Morrison announced in February the Christmas Island detention centre would reopen. ( ABC News: Eliza Borrello )

The Coalition in February announced that parts of the island's detention facility would be reopened in response to the medical evacuation legislation.

The Government said the bill would restart the people-smuggling trade, and those needing medical treatment could be sent there.

The federal Budget in April revealed the centre would revert to a "contingency setting".

Labor appears open to amending the medical transfer law, but would not support the Government's plan to scrap it altogether.

"It's up to the Government to explain if changes are necessary — I have no information that would suggest that changes are necessary," Opposition spokeswoman Kristina Keneally said.

"Labor supports the medevac bill."

More than 500 refugees have left for USA

During the wide-ranging interview, the Home Affairs Minister also provided an update on the United States refugee resettlement deal.

The Trump administration said the arrangement — struck between former leaders Malcolm Turnbull and Barack Obama — would cover up to about 1,250 people.

Mr Dutton said he doubted that number would be reached.

"Over 300 [people] have been rejected by the United States for various reasons," he said.

"That's an issue for the US, they're a sovereign state, they'll make decisions about who they bring [in] under their migration program."

He said 531 people had left for the US and another 295 had been approved to travel under the arrangement.

Dutton defends taking Rwandan duo accused of murder

Soon after Donald Trump took office, Mr Turnbull demanded he honour the agreement.

In a leaked transcript of that conversation, the Australian leader reportedly said: "We will take anyone that you want us to take."

Last month, it emerged two Rwandan men accused of murdering tourists in 1999 were sent from the United States to settle in Australia.

Mr Dutton defended the decision to accept the pair.

"You've got to look at all of the facts of individual cases, you've got to look at the historical perspective around the circumstances, what has happened in the intervening period," he said.

Asked if he knew where the men were living, Mr Dutton said: "I just don't have any information on individual cases.

"But we aren't bringing in people posing a risk."

He said Australia was working with the United States and United Nations to help resolve "very hard" and "intractable" refugee cases abroad.

"[But] we don't have plans to bring any others from America at this stage," he said.