Immigration Minister Peter Dutton is demanding Bill Shorten discipline Labor frontbenchers over an apparent rift on asylum-seeker policy.

Mr Dutton says senior Labor figures such as Anthony Albanese are openly defying the opposition leader on what’s supposed to be the bipartisan policy of turning back boats.

“If he can’t govern them in opposition how on earth is he going to govern them in government?” he asked on Alan Jones radio 2GB program on Tuesday.

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Mr Albanese, in an interview with the ABC’s Lateline program, was reluctant to say whether Labor was on a unity ticket with the coalition.

While Labor backed offshore processing it would adopt a more humane approach, he said.

Mr Albanese, who argued against turnbacks at Labor’s national conference last year, is facing a tough challenge from the Greens in his inner-Sydney seat of Grayndler following boundary changes.

Deputy Opposition Leader Tanya Plibersek suggested the turnback option was a last resort Labor would use if necessary in government.

“It’s something we hope we’ll never have to do but we have to have it in our policy in case it’s necessary,” she told ABC radio.

Shadow treasurer Chris Bowen admitted not everyone within Labor supported boat turnbacks but the opposition was “completely unanimous” in its position.

“These are difficult but necessary decisions,” the former immigration minister said.

“Our moral compass will not allow us to return to deaths at sea.”

The issue came to a head on Monday after Sophie Ismail, Labor’s candidate in the seat of Melbourne, said turnbacks should not be on the table.