The Australian and Afghan Governments have signed an agreement allowing the deportation of those who unsuccessfully seek asylum.
Until now, there's been no mechanism for returning failed asylum seekers to Afghanistan.
As part of the deal, Australia will help Afghanistan upgrade its passport system.
More than 2700 Afghans arrived in Australia by boat last year - more than double the number than from any other nation.
The agreement was signed in Sydney by Immigration Minister Chris Bowen and Afghan Minister for Refugees and Repatriation Dr Jamaher Anwary.
Mr Bowen told ABC Radio the move was aimed at dissuading Afghans from undertaking a perilous journey to Australia, and he said no one would be sent back to face persecution.
"Why can I say that confidently? Because if they were being returned to persecution they would have been accepted as refugees," he said.
As well as improving passport systems, Australia will also offer support for returning Afghans and funding for housing.
Asylum seekers are subject to mandatory detention in Australia while their cases are decided. Those arriving by boat - a figure that increased sharply in 2010 - are sent to Christmas Island for offshore processing.
At least 30 asylum seekers were killed when their boat was wrecked just off the island on 15 December last year.