Australia’s foreign affairs minister, Julie Bishop, has contradicted claims from Peter Dutton that refugees bound for the US under a resettlement deal are “economic refugees”.

On the ABC’s Insiders program on Sunday, Bishop said the people leaving Australia’s offshore detention centres for resettlement in the US were genuine refugees, in contradiction of the immigration minister’s tirade on Thursday in which he claimed they were not fleeing war.

“The US agreed to take a number of refugees and that means that they have been assessed by the UN high commissioner for refugees and found to be genuine refugees,” Bishop said. “That group is then assessed by the United States and they have very stringent vetting processes, as we know.”

Dutton had claimed many of those people who Australia had sent to offshore detention on Manus Island and Nauru had not come from war-ravaged areas but were instead seeking economic advantage.

Amnesty International labelled the comments extremely irresponsible, demonstrating a lack of understanding of the refugee convention and imperilling the resettlement of refugees in the US.

Despite the fact Dutton’s comments were directed at the first group of 54 people to go the US, Bishop said she believed Dutton was “referring to those who have been found not to be owed protection”, including a “significant number from Iran”.

“They should go home,” she said.

Asked if the comments had damaged the US deal, Bishop said that Australia was focused on helping the US vet “as many people as we hope that they will” for resettlement and continuing to look for other resettlement options.

While stopping short of describing the situation in Rakhine state in Myanmar as ethnic cleansing, Bishop said the Australian government was “deeply disturbed by what’s going on”.

Bishop said that 500,000 Rohingya had been displaced from Rakhine state and were seeking sanctuary in Bangladesh.

“I made it clear to the Myanmar national security adviser when I saw him at the United Nations that this security operation that is going on in Rakhine state between the Myanmar army and a Rohingya army must stop,” she said. “Humanitarian support must be allowed in and that the Rohingya must be allowed to return to Rakhine state.”

They have been assessed by the UN high commissioner for refugees and found to be genuine refugees. Julie Bishop

Despite the fact US ambassador to the United Nations, Nikki Haley, has said the Burmese government appears to be engaged in a “brutal sustained campaign” of ethnic-cleansing, Australia has continued to promise thousands of dollars to Rohingya refugees in Australian-run detention centres who agree to return to Myanmar.

The UN secretary general, António Guterres, and Malaysia’s top counter-terrorism official have warned that the humanitarian crisis is a breeding ground for terrorist radicalisation.

Asked about the threat of radicalisation, Bishop said that Australia was “deeply concerned that the persecution of a significant group of Muslim Rohingyas will be used by Isis and other terrorist groups as part of their narrative to take up arms and to fight against the west”.

Bishop said that Australia supported an independent UN investigation and noted Aung San Suu Kyi had confirmed UN representatives and international diplomats, including Australia’s ambassador, would be invited to visit Rakhine state on Monday.

Bishop also indicated that the Australian government believed the strong involvement of China in backing new sanctions on North Korea seems to have changed the calculations for the rogue regime.

On Saturday the US secretary of state, Rex Tillerson, said it was exploring whether North Korea was interested in dialogue and revealed it had multiple direct channels of communication with Pyongyang.

Bishop confirmed Tillerson had told her he had been “back channelling” North Korea – or sending messages via non-conventional routes – in a bid to get them to the negotiating table and take some of the heat out of the official conversations.

Bishop said that the former US president Barack Obama’s policy of “strategic patience” towards North Korea had failed but that China had “recalculated the risk” of leaving North Korea as an issue for the US after Donald Trump had “upped the ante in terms of rhetoric”.

“I believe that China’s involvement is a positive,” she said. “They are playing a pretty active role and I think it’s just changed the calculation in the minds of the North Koreans as well.”

Bishop defended her attendance at the AFL grand final after Fairfax media reported she had attended at taxpayer expense for the fourth consecutive year.

Bishop said she did not travel to Melbourne for the AFL and all of the travel was within parliamentary entitlements.

She noted the AFL is a “significant international event” and she works with the AFL as part of Australia’s aid program in Pacific Island nations. “I was invited in my official capacity as a partner of the AFL and I was pleased to attend.”