"Tell me now, who threatened you. It is no matter how big they are, I will have them punished," said Prayuth Chan-ocha, the former army chief and now military-appointed prime minister who toppled Thailand's democratically-elected government last year.
The comments came as Thai police set up an inquiry into explosive claims by former police major-general Paween that have shattered the junta's assertions that it has thwarted trafficking across its borders.
Mr Prayuth told reporters that Mr Paween had damaged Thailand's standing by fleeing overseas.
"My question is whether he still loves his country. He was born in this land, why has he become estranged from it?"
Mr Paween told reporters after arriving in Melbourne last week, where he plans to seek political asylum, that many soldiers, police and politicians are involved in Thailand's human trafficking networks.
"Unfortunately those bad police and bad military are the ones that have power," he said.
Mr Paween said he was threatened when he headed a task-force set up earlier in 2015 after the discovery of mass graves in the mountains of southern Thailand.
For years Thai authorities had denied any involvement of corrupt officials in the trafficking of thousands of Rohingyas and Bangladeshis, who took to boats across the Bay of Bengal to try to reach Malaysia.
Images of mass graves in the mountains of southern Thailand and starving and distressed families on boats shocked the world.
Mr Paween's taskforce exposed networks of traffickers and led to the arrest of more than 90 people, including politicians, government officials, police and a high-ranking army officer.
Police have said that Mr Paween can testify via video-link from Melbourne in a trial of some of the defendants in Thailand next week.
Mr Paween was forced to wind down his investigations in September and he was transferred abruptly to Thailand's southern provinces, where Muslim rebels have been waging a decade-long insurgency.
He said he would be killed by traffickers and senior police involved in the trade there, and quit the force rather than take up his new post.