Three Liberal backbenchers – Russell Broadbent, Craig Laundy and Julia Banks – have taken the extraordinary step of speaking out against the harsh conditions on the Pacific Island.

They have told the Herald Sun conditions on Nauru are at a “tipping point” and called for the children to be evacuated to Australia for medical care.

Almost 6000 Australian doctors signed an open letter, which was delivered to Morrison on Monday, demanding children and their families be immediately evacuated.

Refugee advocates say the fate of children being held on Nauru now rests squarely with the prime minister.

“He must act now to transfer children and their families to Australia immediately to safety for proper medical care,” Asylum Seeker Resource Centre chief executive Kon Karapanagiotidis said today.

“This is a tipping point and the prime minister needs to act accordingly and get all kids and their families off Nauru.”

Dave Sharma, Liberal Party candidate for the Wentworth by-election, stopped well short of backing calls to evacuate the children and their families to Australia.

Sharma said if elected he would be investing his efforts and time helping to negotiate refugee resettlement deals with third countries, akin to an existing agreement struck with the United States.

He is not in favour of sending the Nauru detainees to New Zealand, citing concerns they may then migrate to Australia.

“I want to address this as best we can, as quickly as we can, in a way consistent with maintaining strong border protection,” Sharma told ABC radio.

South Australian Labor leader Peter Malinauskas yesterday called the indefinite detention of asylum seekers on Naura a disgrace and vowed to push for policy change at the ALP’s national conference in Adelaide later this year.

– with AAP