Immigration Minister Scott Morrison insists navy personnel have done nothing wrong as new details emerge of a boat interception that led to claims of mistreatment of asylum seekers.
A Somali asylum seeker claims his hand was burnt on the boat's engine when he was sprayed in the eyes by an Australian sailor during an angry protest.
A scuffle broke out when he and fellow passengers realised their boat was being turned around by the navy earlier in January.
The account follows earlier claims of mistreatment by the boat's passengers, who were taken back to Rote Island in Indonesia's east.
The federal government has strenuously denied the allegations.
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"I can't understand how the simple presence of an injury in any way suggests that navy and Customs and Border Protection were in any way responsible for that injury," Mr Morrison told reporters in Canberra on Friday.
He confirmed that border protection personnel carried a standard kit which included personal defence devices.
"Any suggestion of mistreatment or misuse of force is completely unsubstantiated," he said.
Mr Morrison noted a change in the nature of the allegations.
"Last week there were claims of torture ... and this week they're changing their story."
Mr Morrison confirmed not all border protection operations were recorded by the Navy and Customs.
He would not say whether there was video footage of the incident in question.
"The government is not going to give the pin number for Operation Sovereign Borders to people smugglers," the minister later told ABC Radio.
Nor was it going to show them how they would be engaged tactically at sea.
