Melissa Parke, the federal Labor member for Fremantle, told the ABC that if the UN does not support Australia's plan to send 800 asylum seekers - including unaccompanied minors - to Malaysia in return for 4,000 Malaysian refugees, she would be unable to offer her support.

"As a former lawyer with the UN for eight years, including working with refugees, and as the chair of the UNICEF parliamentary association, I would find it difficult to support an arrangement that was not supported by UNHCR or by UNICEF Australia," she said.

"Australia has signed up to the UN convention on the rights of a child and they are entitled to have their welfare and rights protected. And the minister, as the official guardian of unaccompanied minors, has a responsibility to ensure that Australia complies with its legal obligations under that convention."

The UN withdrew its support for the Labor Party's Malaysian deal because it involved sending unaccompanied minors offshore. However, after the UN applied pressure, the government is now saying that children will be assessed on "an individual basis".

Parke is not the only lawyer to voice concern over the deal, with lawyers Marion Le and Julian Burnside QC urging Labor to reopen the Nauru processing centre because asylum-seekers would likely receive better treatment in Nauru than Malaysia.

Last month, members of the Malaysian Bar slammed the proposal, saying that Australia would be abdicating their responsibilities under the Refugee Convention and condemning 800 refugees to a life of uncertainty and probable mistreatment.

Opposition to the agreement has intensified since the ABC revealed last week that within the draft agreement, Malaysia, which is not a signatory to the Refugee Convention, had removed all references to human rights.