By MERAIAH FOLEY
Published: June 9, 2009

SYDNEY — The Australian government, under criticism from the United Nations and others because of its harsh immigration laws, has been quietly rolling back a number of measures that kept refugees locked in prison-like detention centers, sometimes for years.

But the number of asylum seekers crossing the treacherous straits from Indonesia to Australia has surged in recent months, setting off an emotional debate about whether the relaxation of Australia’s asylum program has emboldened a new wave of illegal immigrants.

Thirteen boats carrying about 580 people have been intercepted in Australian waters since January, compared with seven boats carrying 161 people last year. Although the numbers are minute compared with the tens of thousands of refugees who converge on Europe every year, each new boatload prompts a flurry of political finger-pointing here, where immigration has long been a contentious issue.

“The number of people who come to Australia is a tiny fraction of those on the move,â€