Australia should hold a wide-ranging judicial review of its treatment of asylum-seekers from Sri Lanka, the United Nations' human rights office said amid uproar over Canberra's handling of the issue.

The office's spokeswoman Ravina Shamdasani said it welcomed an interim injunction granted late Monday by Australia's High Court to prevent the handover of a boatload of 153 Sri Lankans, including 37 children.

"We understand that since their interception more than a week ago, the individuals on this vessel have not been able to make contact with family members or refugee organisations," she told reporters on Tuesday.

"We hope the matter will be subject to a full judicial review in light of Australia's obligations under international law," she added.

Among the areas that need checking are whether Australia respects the principle of "non-refoulement" - UN-speak for not turning away a refugee without a fair hearing, a key tenet of the 1951 Refugee Convention.

In addition, Shamdasani said, Australia needs to assess its compliance with the UN Convention against Torture, the International Covenant on Civil and Political Rights and the Convention on the Rights of the Child.

On Sunday, another vessel was returned to Sri Lanka following a week of secrecy.

The adults among the group of 41 - 28 men and four women - were charged on Tuesday with having attempted to leave Sri Lanka illegally, a crime that carries a prison sentence of up to two years.

A court in the southern Sri Lankan town of Galle granted bail to 27 of them while five were remanded in custody for two weeks. The nine children were discharged.

Shamdasani said the UN rights office was "deeply disturbed" by their return, given an apparent lack of adequate screening of each of the would-be refugees - most of them ethnic minority Tamils fleeing persecution at home.

The process reportedly involved a four-question interview via video link with the applicants denied the means to challenge it.

"International law requires that each and every case be properly and individually examined on its own merits. This is not something that can or should be done hurriedly, remotely and on the high seas, without procedural safeguards and due process guarantees for those involved," Shamdasani said.

"Any returns, even from the high seas or in the territorial seas of other states, must be carried out in accordance with international law, under which refoulement and collective expulsions are strictly prohibited," she added.

She said it was also unclear whether Australia had received any assurances that the returnees would not face ill-treatment in Sri Lanka, nor how Canberra would monitor their fate. (SBS)