Customs officers intercepted the boat northwest of the remote atoll of Cocos Islands in the Indian Ocean on February 9, Dutton said in a statement.
“The government’s policies and resolve are stopping illegal boat arrivals and are restoring integrity to Australia’s borders and immigration programme,” the minister said.
“Anyone attempting to enter Australia illegally by sea will never be resettled in this country.”
The four Sri Lankans, whose gender and identities were not released, were interviewed to see if they “engaged Australia’s non-refoulement obligations under international law” before they were transferred to Sri Lankan authorities on February 10, he said.
“Refoulement” is the term used under international law for unjustly sending a refugee home.
Since July 2013, the Australian government has sent asylum-seekers arriving on boats to Papua New Guinea’s Manus Island and Nauru.
They are denied resettlement in Australia even if they are genuine refugees.
The announcement came after the High Court ruled last month that Australia’s detention of 157 Sri Lankan asylum-seekers at sea for weeks in June was legal.
Lawyers had claimed their clients were falsely imprisoned on the ship.
Their case centred around whether Canberra had the power to remove asylum-seekers from its contiguous zone, just outside territorial waters, and send them to other countries.
The Australian government has said its hardline immigration policy is necessary to stop the flow of so-called “boat people” arriving in Australia.
They had previously been arriving almost daily in often unsafe wooden fishing vessels, with hundreds drowning en route. -AFP