Australian authorities were on high alert on Tuesday after the government warned there were thousands of illegal immigrants waiting to make passage in Sydney in the wake of a fatal refugee boat blast.
Home Affairs Minister Bob Debus said officials in Indonesia -- usually the country of origin for Australia-bound refugee boats -- had reported a surge in asylum seeker numbers.
"In consequence of the troubles in Sri Lanka and particularly the troubles in Afghanistan and Pakistan, there is a sharp increase in the number of people moving to find asylum in Australia or indeed in Europe," Debus told state television late on Monday.
"I think it would be more accurate to say (there are) thousands who are in that country and interested."
"That's not to say they will make it, that's not to say they will eventually secure passage one way or another," he added.
"After all, Indonesian police often working in association with Australian authorities generally have managed to interrupt a great many attempts."
Last Thursday, five Afghan refugees died and dozens more were wounded when their wooden fishing boat exploded off Australia's northwest coast.
Four remain on life support in induced comas, with a further 37 in a stable condition in hospital, of whom five have developed blood infections.
Debus refused to speculate on the cause of the blast, amid an Australian Broadcasting Corporation report the refugees doused the ship's deck in petrol to try to force the navy to land them and not return them to Indonesia.
The treatment of boatpeople remains a sensitive subject in Australia after the previous conservative government incorrectly accused refugees in 2001 of throwing children into the sea in an attempt to force a rescue and asylum.
Now in opposition, the conservatives have blamed a softening in refugee policy for an increase in the number of boatpeople making for Australia's shores, with the latest boat being the sixth intercepted this year.