The United Nations High Commissioner for Refugees has endorsed the proposed Malaysia swap plan in a boost for the Australian government.

The UNHCR said the deal offers better protection for asylum seekers in Malaysia rather than being held in indefinite mandatory detention in Australia. It said it scrutinized Australia's treatment of asylum seekers, and found Australian mandatory detention does not allow asylum seekers to work or live in the community, which Malaysia would. Moreover, Australia denies asylum seekers the right to lawful stay.

''In the context of the Malaysian arrangements, the assurances of legal stay and community-based reception for all transferees can be seen as a more positive protection environment that protracted - and in some cases indefinite - detention that many face here in Australia, provided the assurances are carefully monitored,'' the UNHCR's regional representative, Richard Towle, wrote in response to a parliamentary inquiry.

The Malaysian government has plans to extend legal work rights to all refugees, not just those sent from Australia. The move assures refugees access to insurance and health schemes, Towle said.

Australian Parliament is scheduled to vote on Thursday on the controversial legislation to bypass a High Court ban on the transfer of asylum seekers to Malaysia.

Meanwhile, an open letter has been signed and being spread by a number of prominent Australians calling on the government to terminate offshore processing of asylum seekers.

The letter, whose signatories include former Prime Minister Malcolm Fraser and former Australian of the Year Patrick McGorry, said the current asylum seeker debate is doing serious damage to Australia's international reputation.

Fraser, according to the ABC, said the current asylum seeker policy "demeans Australia," with the government ignoring calls by the Australian people and instead pushing what it wants. Fraser said most of the populace supports onshore processing.

"The government is there to lead. The government is there to appeal to the best of our natures, and not to appeal to the worst of our natures. So far the Australian people have proved themselves time and again to be way ahead of the government and the opposition," Fraser said.

The open letter also accused both sides of politics, including the prime minister and the leader of the opposition, of using the asylum seeker debate as leverage to score points with the voting populace.