Opposition to immigration is weakening thanks to the stronger economy and restricted access to welfare for new migrants, according to a report by Swinburne academic Katharine Betts.

Based on commercial polls and electoral surveys, the report found that 30 per cent of the population felt immigration had gone too far or much too far last year, compared with 67 per cent in 1993, just after the recession of the early 1990s.

Almost half the population now feels Australia's migrant intake is "about right", compared with 24 per cent in 1993. The findings, published in People and Place, the quarterly magazine of the Centre for Population and Urban Research at Monash University, comes despite a huge increase in migrant intake, from about 80,000 in 1999-2000 to 148,000 in 2005-06.

Dr Betts, an immigration expert, said a tougher response to illegal migrants might have helped change public attitude. "While reformers agitating for a more open response may not have intended this, their efforts may have helped reassure voters that control is indeed being exercised," the paper said.