The federal opposition has flagged a crackdown on asylum seekers who arrive in Australia without identity papers.
Opposition immigration spokesman Scott Morrison says having correct documentation should be a "key requirement" for asylum seekers.
The coalition is concerned that nine out of 10 boat people are found to be genuine refugees. Mr Morrison told ABC TV rejection rates varied around the world.
On Christmas Island assessors were often making a "subjective judgment based on the balance of probabilities", he said.
That's because there's little hard evidence available. "Particularly when people are discarding their identity documentation," Mr Morrison said.
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"That presents real pressures and problems.
"Ensuring people have documentation is a key requirement." Mr Morrison said asylum seekers coming to Australia by boat often flew into other countries first.
"You need documentation to get into these countries and somehow between there and Australia that documentation goes missing.
"Now that raises concerns from our perspective and we're looking at policy remedies as to how you would deal with that if we were in government."
The opposition immigration spokesman also dismissed Population Minister Tony Burke's suggestion that governments could "move people around at will".
Mr Burke on Tuesday suggested the Commonwealth could do more to ensure new migrants lived in areas short of workers.
"The levers we have available in the immigration program is one of the issues that I want to be able to look at," he told ABC TV.
"There are things that are already done in the points system. "I don't want to rule out the extent to which we might be able to better target some of those programs than we have previously." But Mr Morrison said that had been tried before.
"It's a lot easier in theory than it is in practice and I think it presents real problems," Mr Morrison said.
"The government needs to start focusing on what the actual numbers are and what's sustainable and work back from there."
The opposition immigration spokesman also confirmed a Tony Abbott led government would increase the number of skilled migrants entering Australia as a proportion of the total intake.
"We believe at least two-thirds of the permanent intake for migration should be skilled."
