SYDNEY — Australia has returned home six Sri Lankans which it said were onboard a "people smuggling boat" after intercepting it at sea, Immigration Minister Peter Dutton said on Wednesday.

Under ’Operation Sovereign Borders’ asylum-seekers trying to reach Australia by boat are either sent back to where they departed from or transferred to remote Pacific island camps.

Dutton gave no indication of where the boat was detected, whether those on board applied for asylum or were assessed for refugee status, and how they were returned.

"Australia has returned a group of Sri Lankan nationals to Sri Lanka yesterday (Tuesday) after recently intercepting a people smuggling venture," the minister said in a statement.

"Six Sri Lankans who were attempting to travel illegally to Australia were aboard the vessel which was intercepted on an approach to Australia."

More than 25 boats have been returned since the introduction of Operation Sovereign Borders in September 2013, a policy the government says has stopped deaths at sea after a spate of drownings.

Dutton stressed that Australia would not change its policy on boatpeople, which sees them returned or sent to the tiny Pacific state of Nauru or Papua New Guinea’s Manus Island and denied resettlement in Australia even if found to be refugees.

The policy has been criticised by rights groups as essentially placing refugees in indefinite detention on remote Pacific islands, where living conditions have been criticised.

Dutton said in the latest incident Australian authorities had been tipped off by their Sri Lankan partners "so we were ready and waiting to locate and detain the boat".

"We have worked cooperatively with Sri Lanka for several years now and since Operation Sovereign Borders began in 2013 every Sri Lankan boat that has attempted to come to Australia illegally, has failed," he added.

In June, Prime Minister Malcolm Turnbull said since the conservative government came to power in September 2013, some 28 boats carrying 734 people had been turned back. — AFP