"I think they (vocational colleges) are not only bringing a bad name to Australia but they are destroying the future of the younger generation of Indian students," The Australian quoted Krishna, as saying.
He added that New Delhi was concerned about the 'physical attacks' on Indian students in Australia and the poor quality of courses and services offered in many vocational colleges.
He also called for new regulations to cover private colleges and continued reform by the federal and state governments.
Krishna, who met Prime Minister Kevin Rudd and his counterpart Stephen Smith during his visit, said the damage to Australia's reputation in India need not be long term.
"I would want the tempo to be maintained so that signals are constantly flowing to India, so that governments are constantly responding to meet our concerns," he added.