'Our organisation has received threats in the past. I have personally received threats. It is a disconcerting development.'

The Four Corners programme aims to 'expose a number of cases where students (coming to Australia) have lost tens of thousands of dollars', ABC Online said.

To highlight the plight of Indian students, the programme spoke to the family of student Prabmeet Singh, who had spent over $40,000 on a course at the Sydney flying school Aerospace Aviation.

His mother Pushpinder Kaur said the family was now broke and her son still did not have the pilot's licence.

'It is a fraud. We were shown so many rosy pictures about the school and it is not what it is really, it was just a scam,' Kaur was quoted as saying.

'I think the government should be more alert in these type of matters because it is the career of the children which is at stake.'

Other Indian students have told Four Corners programme that the aviation college failed to deliver its promised 200 hours of flying time over 52 weeks.

Aerospace Aviation's spokeswoman Sue Davis has defended the training and has questioned the level of commitment and dedication among the affected students, the report said.

The programme also revealed unscrupulous practices by migration and education agents.

Karl Konrad, an education and migration agent based in Sydney, says he has been aware of a black market in dodgy documents for years.

'I had many students come to my offices and say, 'oh I can buy letters for $3,000 at particular restaurants',' he was quoted as saying by ABC online.

'They didn't name the restaurants, but I was getting many of these type of stories. (So) we sent that information to the Immigration Department and they in turn thanked us for the information and said they would pass it on to Trades Recognition Australia. Nothing ever became of that.'