The immediate suspension on the processing of visa applications from new Afghan and Sri Lankan asylum seekers is clearly intended as a deterrent.
But our correspondent says the decision is being widely interpreted as a political move to neutralise an always sensitive issue ahead of this year's election.
"We have taken a consistently hard-line approach to people smuggling and today's announcements will further strengthen the integrity of Australia's immigration system," said Mr Evans.
Boats will not be turned away by the Australian navy and boat people will still be taken to a detention centre at Christmas Island.
However new arrivals will not be able to apply for asylum.
The Australian government says it will review the situation for Sri Lankans after three months, and for Afghans after six.
Amnesty International urged the Australian government to explain why it believed security conditions in the affected countries had improved enough to justify suspending asylum claims.
"Sadly it appears that the government has caved in to political pressure and is now attempting to override the rights of the most vulnerable to score political points," said Andrew Beswick, of Amnesty International Australia.
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