In a bid to curb 'back door' permanent residency through its skilled migration scheme, Australian government has decided to overhaul the immigration rules which is likely to affect over 20,000 visa applicants, including Indians.

The changes would focus on overhauling of the queueing system that identifies occupations in demand and creates a points system.

The immigration minister would have the new legal authority to set a maximum number of visas for a single occupation. The state governments would be asked to develop new migration plans.

The Australian immigration department would tightened the rules from today, 'The Age' reported.

Foreign students, who have a qualification for an occupation which is no longer in demand, could apply for a temporary 18-month visa.

This would allow them to gain work experience and give a foreign graduate time to find an employer willing to sponsor their application as a skilled migrant, and if they failed in their attempt they will have to return to their country of origin.

The cancelled applications apply to all offshore general skilled migration claims lodged before September 2007.

For onshore overseas students, government would introduce transitional arrangements to apply until 2012.