The Australian government has returned six Sri Lankans attempting to reach Australia by boat, the immigration minister has said.

On Wednesday Peter Dutton confirmed the government had returned the group after “recently intercepting a people-smuggling venture”.

Dutton said the Australian and Sri Lankan governments continued to work closely on the issue of boats trying to reach Australia.

“Our Sri Lankan partners provided advice that this vessel might be targeting Australia so we were ready and waiting to locate and detain the boat,” he said.

Boat turnbacks and the return of people seeking asylum remain controversial. Experts and human rights groups, including Amnesty International, argue they do not comply with international law.

Asylum seekers who attempt to come to Australia by boat are typically interviewed at sea by border protection officials and the interviews are then assessed by the immigration department.

In May a human rights lawyer told Guardian Australia a group forcibly returned to Sri Lanka after it reached the Cocos Islands had their claims for refugee status ignored because they were only asked cursory questions including their names, where they came from and why they came.

Asylum seekers returned to Sri Lanka routinely face court on charges of illegally leaving the country, such as the group returned in May who were immediately arrested.

Several reports have alleged that asylum seekers returned from Australia to Sri Lanka have faced arbitrary arrest, persecution, police brutality and torture.

The return of the Sri Lankans comes after Guardian Australia published more than 2,000 leaked reports detailing assaults, sexual assaults and self-harm in Australia’s offshore detention centre at Nauru.

The Nauru files have led to calls for a parliamentary inquiry and to close offshore detention.

Legal academics and migration experts, including Frank Brennan, have argued the policy of turnbacks make punitive detention unnecessary to deter dangerous boat journeys.

Dutton said the return of the six Sri Lankans “shows that there has not been, and will not be, any change to Australia’s robust border protection policies”.

“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 said.

“People should not believe people smugglers’ lies and risk their lives trying to get to Australia in unsafe boats; they will be turned back and will have wasted their money.”