Prime Minister Tony Abbott has expressed his regret that a female asylum seeker was separated from her newborn baby and says the only way to prevent a repeat is to stop the boats.
"If you want to avoid these things you've got to stop the boats," Mr Abbott said on Friday in Colombo, Sri Lanka, where he is attending the Commonwealth Heads of Government (CHOGM) meeting.
"I don't, as it were, apologise for what happens when people come to Australia illegally by boat."
The mother was moved off Nauru so her baby could be delivered in Australia by Caesarean, but was reportedly moved back to a Brisbane detention centre while her newborn son remained in hospital.
"Obviously, I deeply regret that," Mr Abbott said.
Immigration Minister Scott Morrison has asked his department to review the circumstances surrounding the separation of the woman from her baby.
It is understood the baby had respiratory problems requiring close medical care.
"I have requested my department to look at the arrangements ... to ensure that a mother would have as much access to their child as they would request, consistent with the standards and opportunities that would be otherwise available to any Australian at that hospital," Mr Morrison said.
He defended the treatment of the woman, who was only allowed to visit her sick child during the day and forced to sleep overnight in the detention centre.
"The doctors at the hospital had advised that this is common practice with mothers not to stay overnight with their children in special care due to bed restrictions," he said.
"My advice was that this mother was being treated the same ... in terms of access to the hospital, as any other Australian."
The Australian Greens say the woman has been treated in an "inhumane and senselessly callous" way.