There are now fewer than 40 children left on Nauru due to ongoing medical transfers, despite the Morrison government continuing to defend the conditions faced by asylum seekers and refugees on the island.

The assistant minister for international development, Anne Ruston, told the Australian Council for International Development’s annual conference the current debate had “been politicised and is not grounded in fact”. The conference passed a resolution on Tuesday calling for the government to bring all children and their families to Australia, and ensure no one was held indefinitely on Nauru.

“There is no bigger issue at the moment than Nauru,” she said.

She criticised commentary in the media that was speaking out against Nauru as a sovereign nation and friend to Australia in the Pacific “in the absence of hard facts”.

“There are no children in the RPC. All the children are out with their families in the community,” she said, adding that transferees were free to move about the island.

The Nauruan government bulldozed the RPC accommodation area on the eve of the Pacific Islands Forum, and the remaining RPC1 is used to house and treat seriously ill people – including children.

Ruston said the service providers on the island provided age appropriate health, education, recreational and cultural services, and medical care was available seven days a week from IHMS and Nauruan doctors.

“Like ACFID, the Australian government is a fierce advocate for the rules-based order. This means we respect Nauru’s sovereignty and work in partnership to find regional solutions,” she said.

“What we can’t do is go back to the bad old days – where people-smuggling syndicates opened pipelines up into Australia, resulting in at least 1,200 people dying at sea and they are just the ones we know about.”

Last month Médecins Sans Frontieres called for the immediate evacuation of all transferees due to the high level of physical and mental illness and the inadequacy of services to to deal with it after they were kicked off by the Nauruan government.

There have been a number of instances of Nauruan officials refusing to cooperate with Australia authorities on medical transfers of people to Australia.

In her speech, Ruston said that with 21m registered refugees and more than 65m displaced people worldwide, countries couldn’t “resettle our way out of this problem”, and she welcomed the chance to work with civil society groups on a solution.

Ruston’s comments about Nauru come as other members of the government appear to shift their messaging on the growing calls for evacuations.

On Tuesday the prime minister, Scott Morrison, said the government was reducing the number of children on Nauru by “getting about this quietly”.

“We haven’t been showboating about it, we haven’t been doing any of those things,’’ Morrison said.

The Coalition MP Craig Kelly told Sky News on Wednesday the government wanted to “wrap that up” by the election.

Former prime minister Tony Abbott told Radio National the people “are not being resettled in Australia”. “They are being moved to Australia on a case by case basis if that is required for urgent and significant medical treatment,” he said.

Asked if they would stay in Australia, Abbott replied: “Nope, they are coming to Australia to be treated but the government has made its position absolutely crystal clear that people who come to Australia illegally by boat will never be able to settle here permanently.”

Asked how the number of medical transfers squares with his comments that people Nauru receive better medical treatment than in some regional Australian towns, Abbott replied that some conditions cannot be treated on Nauru.

.@CraigKellyMP on asylum seekers: There are 52 children left on Nauru, we want to try and wrap that up before the next election.



The Labor Party is still playing games by refusing to agree on resettling refugees in New Zealand.



MORE: https://t.co/JnKjtcUDw6 #amagenda pic.twitter.com/o14f5Lp0oR — Sky News Australia (@SkyNewsAust) October 30, 2018

Since 15 October, 135 people have been brought to Australia from Nauru, including 47 children.

Just 49 of the 135 were moved by the government without legal intervention by advocates or lawyers on behalf of them.

According to the Asylum Seeker Resource Centre, the 41 families included eight who were moved by court order, 21 under concessions made after legal intervention, and 12 moved at the initiative of Australian Border Force.

Guardian Australia has confirmed at least two chartered Nauruan Airlines flights have brought people to Australia in the past 10 days, including several to Adelaide on Monday.

There have been at least 17 children – with their families – housed in the Melbourne detention centre. It is expected that most will be moved within two to three weeks once housing, support services and schools have been organised.

Ruston also spoke of the need for government and the civil society sector to better communicate with Australians about the benefit of foreign aid spending in the region.

She noted that among the “profound misconceptions” on foreign aid, a Lowy Institute poll found Australians on average believed Australia spent 14% of its budget on foreign aid.

“We need to show Australians that our investments overseas is money spent for them, not money taken from them,” she said. “I want Australian spending on development assistance to be seen as just plain common sense.”

The chief executive of Acfid, Marc Purcell, joined Ruston on stage to thank her, but also said the council was calling for children and families to be taken off Nauru – drawing widespread applause from the room.

He said the sector hoped to work with government to find “practical ways to carry that forward”.

Ruston did not stay for questions as she had a flight to South Africa.

Speaking after the speech, Purcell told Guardian Australia Acfid was “listening to the doctors, experts and people on the ground in Nauru who are warning of the deteriorating mental and physical health of these children”.

“There have been medical evacuations to Australia on that basis. That is our evidence and we join with those doctors - and so many in the Australian community - to get Kids Off Nauru.”