Government ministers have repeated claims that all 1,000 or so refugees in offshore detention would receive medical transfer under the Kerryn Phelps bill – but failed to explain if that meant they are all sick.

The Coalition government is strenuously fighting against amendments to Australia’s medical evacuation rules, which would give doctors more say in who needs to be transported for treatment.

Under the amendments Labor originally supported, the minister could reject a transfer on national security grounds, but would need to do so within 24 hours, with an independent health panel set up to review the rejections.

On Sunday, David Coleman and Christopher Pyne were the latest government ministers who argued against changes to existing medical evacuation rules, claiming it would result in all Manus Island and Nauru detainees being sent to Australia.

But they dodged answering whether or not that meant the 1,000 or refugees and asylum seekers under Australia’s care in the offshore centres were all ill enough to require transfer.

Pyne said all refugees and asylum seekers “could all qualify” for medical transfer to Australia, but dodged if that meant they were all ill.

“The bottom line is: we’re not prepared to weaken border protection,” he told the ABC in a somewhat combative interview.

When asked “how it’s got to the point where almost all of them are ill”, Pyne responded that the point was “we’ve stopped the boats”.

When the interviewer told Pyne the original question was not answered, the defence industry minister followed up with another answer on border protection.

Pyne said the government’s opposition to changes was the challenge to the home affairs or immigration minister’s use of discretion, a process which already exists, and is already under challenge in the federal court.

“What they’ll find is that they will be able to appeal the minister’s use of the discretion,” Pyne said.

“Labor knows that. They’ll all be caught up in the court system. They’ll be coming to Australia one way or the other saying that they have a need to because of ill health.

“And quite frankly, there are now ... There’s nobody in Manus Island ... Manus Island doesn’t actually operate any more as a detention centre. It’s been closed down. Those people are in the community. There’s nobody in detention on Nauru. They are all part of the community and there are no children left on Nauru and the last few have got a process to come to Australia.”

Coleman, the immigration minister, was also pressed on the government’s opposition and what the government’s claim about almost all asylum seekers being able to access treatment in Australia meant about the health of those under the nation’s care.

“The key point is, within weeks, it is highly likely, and as you know, that is the advice – that substantially everyone who is currently on Manus and Nauru would come to Australia. Yes, I do believe that,” Coleman told Sky News on Sunday.

Asked if that meant each of the refugees and asylum seekers needed medical attention, Coleman deflected the question by returning to his talking points.

“I think what it indicates, is the structure of this legislation is designed to undermine offshore processing to such a state that it no longer exists any more.”

Under the Phelps amendments, asylum seekers and refugees would remain in detention, even if transferred to the mainland, with ministers maintaining ultimate control over who, if anyone, is released into the community.

With a historic defeat on substantive legislation a distinct possibility in the next parliamentary sitting, the government has hit back against the legislation it has labelled “Shorten’s law”, despite it being led by the crossbench.

As a compromise to head off a potential defeat, the Coalition government has offered to set up its own medical review panel, which would leave the final decision with the minister.

In the mean time, it has continued to push back against the proposed changes, using leaked security agency advice provided to the home affairs department as proof the changes would be detrimental to Australia’s border security.

The leak of that advice has been referred to the Australian federal police for investigation. But it led to Labor admitting on Friday it would be open to a “middle ground” on the issue, as the opposition attempts to navigate the politics of border security in the lead-up to the federal election.