Labor has been accused of supporting a “shameful attack” on Australia’s navy by calling for an inquiry into claims that border protection officers abused asylum seekers.

It comes as the Customs and Border Protection Service denied reports it would launch fresh inquiries into claims its sailors deliberately burnt the hands of asylum seekers.

The federal opposition is calling for an independent investigation into the abuse allegations, saying it’s the best way to vindicate the navy of any wrongdoing.

But Immigration Minister Scott Morrison has lashed out at the proposal, saying it proves Labor’s weakness on the issue of border protection and willingness to sledge the navy.

“Unlike the Labor party, the government will continue to back our navy and customs personnel in the face of these wild, unsubstantiated allegations,” Mr Morrison said on Saturday.

“Labor’s call for an inquiry, thereby legitimising these outrageous and unsubstantiated claims of torture, is a vote of no confidence by Labor in our navy and Customs and Border Protection Service.”

He said reports that border protection officials would conduct a new internal inquiry into the abuse claims was “another attempt to pump oxygen into these baseless allegations”.

Customs said there was no new evidence that warranted further investigation into the conduct of its personnel.

“The allegations were assessed at the time they were first made and found to be without foundation,” customs said in a statement on Saturday.

“Border Protection Command remains confident its personnel continue to act with the highest levels of professional conduct in a demanding and difficult environment.”

The ABC is facing calls for an inquiry over its decision to first broadcast the abuse allegations, and has admitted it should have been “more precise” in its coverage.

But the allegations were given fresh impetus after being reported again in Fairfax Media, prompting opposition parliamentary secretary Matt Thistlethwaite to call for an investigation.

“That’s the best way to vindicate the Australian navy,” he told Sky News on Saturday.