Sukhdip reportedly had his nose and jaw broken, and is now unable to eat any solid food.
There has been a string of attacks on Indian students in Australia since May this year, causing an uproar in India. Canberra has given repeated assurances to New Delhi that it would do its best to stop the attacks.
External Affairs Minister S.M. Krishna visited Australia in August to take up the issue.
Australian Minister for Education Julia Gillard visited India in late August and assured New Delhi that his government was taking measures to prevent attacks on Indian students.