People smugglers are trying to overwhelm Australia's hardline asylum seeker settlement deal with Papua New Guinea, Immigration Minister Tony Burke says.
"In the last few days, some of the smuggling operations have tried to put together a bit of a surge and to see if they can overwhelm the current system," Mr Burke told ABC television on Tuesday.
More than 500 asylum seekers aboard four boats have arrived since Sunday.
The latest boat to arrive in Australian waters capsized north of Christmas Island on Tuesday. Up to five people are believed to have drowned.
Mr Burke insists the number of people arriving by boat has been falling since Prime Minister Kevin Rudd unveiled his tough regional resettlement plan on July 19.
He says Australia and PNG stand ready to build more facilities on PNG's Manus Island if needed.
Meanwhile, Mr Burke said Australia's processing centre on Nauru was almost ready to receive family groups but that it wasn't ready for unaccompanied minors.
"Family groups will be going to Nauru very soon," he said.
"Unaccompanied minors will be going when I'm confident that they will be safe, that the facilities are in place (and) the accommodation and services are in place that meet the obligations that I'd expect."
