By Tess Ikonomou, Kat Wong and Andrew Brown in Canberra

Recent boat arrivals have prompted calls for a rethink of Australia’s immigration measures as the prime minister and opposition leader trade barbs on border security,

A group of 39 people from Pakistan and Bangladesh were found at Beagle Bay, north of Broome, late last week and have been flown to an offshore detention centre on the Pacific island of Nauru.

While Prime Minister Anthony Albanese said people smugglers were taking part in an “evil trade” and changing tactics, Opposition Leader Peter Dutton said the incident showed the government had started to “lose control again of our borders”.

But the debate on border protection has reignited calls from aid organisation Amnesty International for the government to process the arrivals in Australia, rather than on Nauru.

Amnesty’s refugee rights advisory Graham Thom said Australia needed to heed warnings from human rights experts on the treatment of boat arrivals.

He said the recent arrivals could not lead to the beginning of further rounds of offshore processing.

“For 10 years, the Australian community watched in horror as people who came to us seeking safety were indefinitely detained in appalling, cruel conditions,” Dr Thom said.

“Sending a new cohort of people seeking asylum back to these offshore processing centres is outrageous, given the recent revelations of corruption and management, not to mention the human suffering it caused.”

Mr Albanese said Australian Border Force officials had sent a clear message to people smugglers.

“People smugglers are part of an evil trade,” he told reporters in Perth on Monday.

“They’re trading in people and they’re prepared to see people risk their lives in order for them to make a profit.

“They will constantly try to change and what we will do is constantly be vigilant and ensure that the message is very firmly sent … People who arrive by boat get sent offshore.”

He said boat turnbacks, together with measures that would remove arrivals from Australian soil to other locations, showed Operation Sovereign Borders, better known as the “Stop the Boats” policy set up by the coalition government, was still in place.

Mr Dutton maintained the prime minister was not doing enough on border protection and had incentivised people smugglers by leading a “weak and incompetent” government.

But Abul Rizvi, a former deputy secretary of the Immigration Department, warned politicians to be careful with their rhetoric, saying it could lead to more illegal boat arrivals.

“If people smugglers are able to convince potential people who may wish to come to Australia by boat that the difference in the rhetoric is something they can take advantage of … we may, if that happens, see a rise in boats,” Dr Rizvi told ABC radio.

“I would counsel politicians on either side not to inflame the rhetoric in this space.”

Mr Albanese confirmed he spoke with Operation Sovereign Borders commander Rear Admiral Brett Sonter on Sunday after three groups of boat arrivals had been found.

The commander also cautioned against politicising the boat arrivals.

Mr Dutton said the government needed to explain how many boats had arrived and how they were able to evade detection.

The full details of the arrival have still not been confirmed.