Peter Dutton has used his powers under the medevac laws to block the transfer of a refugee on security grounds, revealing as false his long-running claims that the laws rendered the government powerless to do so.

On Wednesday it was revealed the home affairs minister had used his ministerial powers for the first time to override doctors’ recommendations to transfer an individual.

The Iranian man in question was recommended for transfer to accompany his daughter who required treatment, the Courier Mail reported.

In a statement tabled in parliament, Dutton said he refused the transfer on 11 October under section 198G(2) of the Migration Act, because he reasonably believed the individual “would expose the Australian community to a serious risk of criminal conduct”.

“The department of home affairs has advised me that the accompanying family member has a history of violent and manipulative behaviour, including allegations of physical assault against his children, been investigated by the Nauruan police force for criminal activity, engaged in military service in Iran and that the department has been unable to verify his identity.”

Military service is compulsory for Iranian men.

Dutton said he had instead approved the transfer of a separate family member to accompany the adult woman, and noted she also had family in Australia.

Dutton and the prime minister, Scott Morrison, have repeatedly claimed the medevac laws – which the government is pushing to repeal – would bring murderers, rapists, and paedophiles to Australia and the government could not stop it happening.

In June Dutton told Sky News: “The point made by the Labor party – and you heard a bit of the rhetoric in the previous interview – people of bad character can come, are able to come and, in fact, are required to come under Labor’s laws that they passed. That’s the reality.”

In February, before the bill was passed, he told Ray Hadley on 2GB: “One person has been accused of murder, out of Iran. Under the Labor party bill, or now law, we cannot stop that person from coming in.”

In February Morrison said: “Someone who’s a paedophile, who’s a rapist, who has committed murder – any of these other crimes – can just be moved on the say-so of a couple of doctors on Skype.”

He also said the bill “doesn’t provide for the usual arrangements which would enable us to reject someone coming to Australia because they have a criminal history”.

The medevac laws allow for Australian-based doctors to recommend a refugee or asylum seeker offshore be transferred to Australia for care. The minister can refuse if he disagrees with the clinical assessment – in which case it goes to the independent medical panel for review – or on security or criminal grounds. The panel cannot override vetoes based on security or criminal concerns.

The opposition spokeswoman on home affairs, Kristina Keneally, said Dutton’s refusal was proof that medevac was working as intended.

“Why did Scott Morrison and Peter Dutton claim people of bad character could be transferred to Australia under medevac when it’s clear they have the powers to deny such transfers?” she said.

“Under medevac, the minister can refuse a transfer on security or serious character grounds and this decision does not get reviewed and cannot be overturned. In fact, before medevac, the courts were deciding medical transfers on health grounds only, not even taking into consideration security concerns.”

In the parliamentary inquiry into the medevac repeal bill, the department said it was the “limited nature of the character grounds” which the minister could cite to refuse a transfer which were of concern.

In answer to questions on notice, the department said “security” definitions under existing legislation “set a very high bar” and were “relatively narrow”.

The definition “therefore may not coverall the national security concerns the minister may have,” it said.

Because of this, the minister had character or security grounds about six people recommended for six medevac transfers but was unable to refuse them. The answer did not detail what the concerns were.

Labor, the Greens, key crossbenchers, and most relevant stakeholders have opposed a repeal of the laws.

The Australian Medical Association, the Royal Australian College of General Practitioners, the Australian Human Rights Commission, and a former home affairs department official, Shaun Hanns, are among those opposed.

Guardian Australia has previously revealed that under the previous medical transfer process – which still exists in parallel to medevac – the government ignored its own doctors’ recommendations to transfer a person, for up to five years in some cases.

The government was taken to federal court dozens of times to prompt a transfer, and spent more than $780,000 in 15 months responding to these cases.

Some saw the department agree to transfer before proceedings commenced, while others required a court order. It was not once successful in arguing against a case, and is challenging the federal court’s jurisdiction to hear such cases.

Under both systems, the government of Nauru has notoriously blocked or attempted to block transfers, or required them to go through extra levels of bureaucracy with its problematic overseas medical review panel.

The government of PNG is similarly preventing the transfer of men approved for medevac but who have been jailed at the Bomana immigration detention centre as unlawful migrants.