Since the installation of a new hotline was established in February 2004 in Australia, 50,000 calls were made turning in illegal workers and visa over-stayers.
Immigration Minister Amanda Vanstone said the community played a critical role in protecting the immigration system.
"Information provided through the dob-in line and other telephone contact with the Department of Immigration and Multicultural and Indigenous Affairs is passed to the departments compliance officers around the country," she said.
"They use it to help locate people who have overstayed their visa or are working in breach of their visa conditions."
Senator Vanstone said an estimated 47,800 visa over-stayers were in Australia on June 30 a small proportion of the total 4.3 million temporary entrants to Australia in 2004-2005.
In 2004-2005, department staff located more than 18,300 visa over-stayers and illegal workers 10,500 in NSW, 3500 in Victoria, 2000 in Queensland and more than 1000 in Western Australia.