Aussie PM Scott Morrison will send Nauru refugees to New Zealand if 'the back door is closed'

Australian Prime Minister Scott Morrison says he will support sending Nauru refugees to New Zealand as long as the "back door" to Australia is closed.

The comments came after Liberal MPs demanded the 80 children still on Nauru be bought home immediately. 

The back door Mr Morrison is referring to is a proposed Bill from 2016 which would prevent any asylum seekers who arrived in Nauru in 2013 from applying for an Australian visa.

The Bill is opposed by the Labor party and the Greens, and they are the only reason the bill has not yet passed.

"I would urge them to reconsider their position on that," Mr Morrison told ABC.

If the law was put in place it would stop anyone transferred to New Zealand from travelling to Australia after becoming New Zealand residents.

It is not clear yet if New Zealand would then have to implement our own law preventing residents travelling to Australia.

The law, as pointed out by Labor's immigration spokesperson Shayne Neumann, was not needed, following the deal already made with the United States stopping refugees from returning to Australia.

Doctors have advised the Government that more consideration needs to be given to removing the children immediately as concerns for health continue to grow.

Nearly 6000 doctors and medical students signed and handed the Australian government a petition demanding the children be removed due to deteriorating physical and mental health conditions.

Labor Government MPs' have suggested moving children with the most severe illnesses before other children as a case by case removal.

"We've been acting on these issues," Mr Morrison told ABC. "We haven't been doing it by making public statements about it every day, but we always consider each and every case on its merits and in the interests of the child, and we will continue to do that."

The children on Nauru have been there for up to five years.