Legal experts say there is likely to be a challenge to the Coalition's new plan to process asylum seekers.

Opposition immigration spokesman Scott Morrison says there are 30,000 asylum seekers waiting to be processed and, if elected, the Coalition's policy would be to start assessing those most unlikely to be judged refugees.

Those who are deemed to be refugees would instead be placed on temporary protection visas (TPVs) while those denied asylum would be ineligible to appeal the ruling.

Under the plan, a single case worker will review claims and make a ruling, an immigration officer will review those decisions, and those people deemed to have no case will be quickly deported or permanently detained.

The controversial element is to try to return to the Howard government's rules under which applicants would have no right to appeal the decision before the Refugee Review Tribunal.

Mr Morrison concedes the plan is legally difficult, and Professor George Williams from the University of NSW says he expects it would be challenged in the High Court.

"Well, the issue would arise if they also tried to stop those people having decisions reviewed in the courts," Professor Williams said.

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"There would be a constitutional issue there because the High Court has said very clearly that the Constitution guarantees the right to appeal to the High Court when reviewing Commonwealth decisions," he said.

"Prior governments, including the Howard government, have tried to strip away those court rights, but back in 2003 the High Court said in a case called Plaintiff S157 that was constitutionally prohibited.

"From that time it has been clear that at least when it comes to the High Court, people can't be denied their access to that court."

Refugee status 'a life or death decision'

Lawyer David Manne has succeeded in the High Court previously when he has tackled refugee issues and he too is critical of the proposal.

Mr Manne has told ABC News 24 that he thinks the policy breaches Australia's United Nations obligations.

"Look, it's profoundly concerning and likely to seriously violate certain rights that refugees and asylum seekers should be afforded," he said.

Sorry, this video has expired Coalition unveils plan to strip asylum seekers of right of appeal

The Human Rights Law Centre's Daniel Webb says access to the courts is a fundamental right that must be protected.

"I think that that goes against the very basic spirit of protection that is at the heart of the refugee convention," Mr Webb said.

"Fundamentally the problem with that is assessing whether or not someone is a genuine refugee is potentially a life or death decision.

"There's absolutely no margin for error. The consequence of getting that wrong may be that you return a genuine refugee to face the very persecution from which they've fled.

"Now short-cutted processes, abolishing appeal rights, things like that... all they do is increase the risk of error. And the price for that will be paid by genuine refugees who we return."

Plan would create 'disruption of the system'

Sorry, this video has expired Refugee advocate Pamela Curr criticises Coalition's new policy ( Miriam Corowa )

Attorney-General Mark Dreyfus says the Opposition's plan is unconstitutional and an "on-the-run thought bubble".

"Past experience shows us what people affected by government decision-making, dissatisfied with the rejection of their asylum application would go straightaway to the High Court and we would have an overwhelming of the High Court and it would be a complete disruption of the system," he said.

"Also what's important is this says nothing to people who are considering coming to Australia."

Mr Dreyfus rejected Opposition claims the Government did not have a policy to address outstanding claims of asylum seekers already in Australia.

"If they're found to be asylum seekers, people meriting asylum, they will be resettled in Australia - these are people already here," Mr Dreyfus told ABC 24.

"If not, they will be returned to the country from which they've come.

"I think it's about time the Opposition stop this kind of blind rush to be as harsh as they can possibly be just for the sake of it."

Morrison 'not going to give up'

Mr Morrison conceded asylum seekers could still go to the High Court and admitted there would likely be a legal challenge to retrospectively stripping the right to access to Refugee Review Tribunal and the Federal Court.

"Lawyers will say it can't be done, the Government will say it can't be done, everyone will say it can't be done," he said.

"We're not going to give up on this."

However, Mr Morrison refused to be drawn on whether legal challenges are likely to be successful.

"Well, this is the task we're setting officials if we're elected to government," he said.

"I'm just not prepared to accept the situation that we can't return to the non-statutory administrative process to end the tick and flick system that the Government has now been running for the last five years."