Prime Minister Malcolm Turnbull says the government is aiming to get all children out of immigration detention.
Mr Turnbull was asked by Greens MP Adam Bandt in parliament on Thursday whether he would ensure no asylum-seeker children now in Australia would be deported to Nauru.
"One child in detention is one child too many," Mr Turnbull said.
"Our goal is to reduce that to zero, but the key element in doing so is ensuring that people do not get on people smugglers' boats and put their lives at risk."
However, the prime minister declined to say how many children caught up in a High Court decision which went in favour of the government would remain in Australia.
Immigration Minister Peter Dutton said the number of children in detention had dropped to 75 as of Thursday.
"We will work with many people to make sure that we can reduce that number down to zero," Mr Dutton told parliament.
He urged Labor to work with the government and deliver a consistent message to people smugglers.
