Navy personnel have been spat on, abused and treated like servants while saving asylum seekers’ lives, the Senate has been told.

A ropeable Defence Minister David Johnston was on the front foot on Wednesday, fielding a question from his own side about claims sailors deliberately burnt the hands of asylum seekers.

“These allegations, made by someone who is currently in Indonesia, are the epitome of hearsay,” he told the chamber.

“They are made by someone who has wasted his money and lost his opportunity to surreptitiously enter this country.”

He seized on Labor MP Matt Thistlethwaite’s call for an independent inquiry.

“The fact that a former senator and Labor member would so quickly take the side of someone seeking to illegally enter our country in the face of the hard and heroic work of Royal Australian Navy personnel sickens me,” Senator Johnston said, dismissing the need for an independent inquiry.

Later, Senator Johnston was asked how he could fulfil his legislative duty to ensure the health and safety of Defence personnel engaged in Operation Sovereign Borders, if he was not aware of operational matters.

He replied the Defence Force chief had sought an exemption so that sailors would not be subject to penalties for breach of the Work Health and Safety Act.

Sailors suffering post traumatic stress disorder would be offered appropriate care, he said.