The federal government's hardline asylum seeker resettlement policy is being implemented exactly according to plan, Immigration Minister Tony Burke insists.
The first group of families was sent to Nauru on Wednesday while three Iranians have chosen to return home rather than be resettled in Papua New Guinea.
Mr Burke says people can expect to see more families transferred and more people choosing to go home over the coming weeks.
"Whoever wants to test our resolve will find that we are serious about this," he told reporters in Sydney on Wednesday.
"If it takes for them to be wheels down on Manus Island or Nauru before they realise that we're serious then so be it.
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"The regional resettlement arrangements with Papua New Guinea and Nauru are being implemented exactly as I predicted they would be implemented."
Prime Minister Kevin Rudd says his resettlement plan needs more time to work.
"It's going to take a while to work through and I challenge anybody to come up with an alternative and effective policy," he said in Brisbane.
But he said the policy was beginning to have an effect, both on asylum seekers planning to make the boat journey and those already in PNG.
His comments came after five people were believed to have drowned on Tuesday when an asylum seeker boat sank north of Christmas Island. Rescuers saved 106 people.
Mr Burke said the capacity of the detention centres on Nauru and PNG's Manus Island was being kept "well in excess of what will be required".
The seven families sent to Nauru - each with a mother and father and including a total of 12 children aged between five and 15 years - will be housed away from the single men there in detention.
Initial arrangements for people who are talking to the International Organisation for Migration about being sent home are ready.
One person has returned to Iran from Christmas Island and two have been sent from Manus Island.
"The whole purpose of their original voyage turned out to be a waste of money and a waste of time and an unnecessary risk," Mr Burke said.
People needed to understand that whatever they were promised, paying money to a people smuggler would certainly involve risk, possibly drowning, he said.
"If there are a large number of people on the beaches of Indonesia at the moment thinking they want to get on boats, I can't stop them from getting on a boat," Mr Burke said.
"What I guarantee is that they won't end up being settled in Australia."
The arrangements would stay in place whoever won the election, the minister said.
"If (opposition immigration spokesman) Scott Morrison holds my job on September 8 he will be walking away from every public statement he's made at a rate of knots."
