Federal Opposition Leader Bill Shorten has outlined a “new direction” for Labor’s immigration policies on what is expected to be his most torrid day of the ALP national conference.

Addressing delegates on Saturday morning, Mr Shorten revealed details of his policy to support turning back asylum seeker boats, along with a plan to double the refugee intake to 27,000 people a year and significantly improve conditions for detainees on Nauru and Manus Island.

“I do believe in a new direction, for Labor’s immigration policies,” he told the audience.

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“I want us to accept more refugees, and treat refugees more humanely.

“I also want to guarantee we keep closed the lethal journey between Java and Christmas Island, which has already claimed so many lives.”

A ship banned from entering Australia for carrying illegal asylum seekers. Photo: AAP

But there is intense opposition to turn-backs from within sections of the Labor Party. Many say it is impossible for Australia to turn back boats and still comply with its international obligations.

The policy dispute is expected to lead to passionate debate over refugee issues at the conference.

Mr Shorten revealed the details of his policy in a bid to shift the focus from the unpopular turn-backs plan to a promise to give $450 million over three years to the United Nations refugee agency, the UNHCR.

The Opposition Leader also promised Labor would reinstate references to the UN refugees convention in the Migration Act.

Doubling the refugee intake to 27,000 a year by 2025 would be one of the other key elements of his policy.

Mr Shorten also spelled out a plan for an independent advocate for children in detention and promised that they would have access to all unaccompanied children in detention.

He also pledged legislation to impose mandatory reporting of child abuse in all detention centres, both onshore and offshore.

Mr Shorten has maintained Labor’s commitment to offshore processing, saying it dealt a huge blow to people smugglers’ ability to sell the journey to Australia.

The Labor leader set out his vision for the centres to be humane and safe and with fast and efficient processing.

He would give the Commonwealth ombudsman the power to oversee the offshore detention network.

The group Labor For Refugees is determined to seek to soften Labor’s policies, including trying to have boat turn-backs explicitly banned.

Andrew Giles does not want turnbacks to be part of Labor’s policy. Photo: AAP

Mr Shorten acknowledged people had different perspectives and deeply held principles on the issue but said there were “important truths” Labor must face.

“There is a history — and a reality — we cannot ignore,” he said.

“The challenge before us is real — and the questions we grapple with are as elemental as life and death”.

The policy has previously been agreed to by shadow cabinet, although the ABC understands not all members of his frontbench knew Mr Shorten was going to announce his support for turn-backs on Wednesday evening.

It appears likely that any motion to stymie Mr Shorten’s plan by explicitly banning turn-backs would be defeated by conference delegates, but most expect the margin to be narrow.

There is a push within Labor’s Left faction to drop plans for an amendment, saying Labor should not adopt boat turn-backs, as the faction opposes turn-backs in principle.

Federal Labor MP Andrew Giles has put forward an amendment aimed at ensuring boat turn-backs cannot be part of ALP policy.

The motion is seconded by Murray Watt — who is on Labor’s Queensland Senate ticket for the next election. Mr Watt is also from the Left faction.