Australian universities are too dependent on Chinese students and risk having to dumb down their curriculum or lose their independence, academics warn.

International student numbers at Sydney universities jumped an unprecedented 50 per cent in the past two years, bringing a financial bonanza with them.

Rising student numbers were a huge boon to universities but academics and the NSW Auditor-General worried it could be a house of cards.

Australian universities are too dependent on Chinese students and risk having to dumb down their curriculum or lose their independence, academics warn

International student numbers at Sydney universities jumped an unprecedented 50 per cent in the past two years, bringing a financial bonanza with them

The Auditor-General's June report said universities were 'vulnerable' to fluctuations in China from putting too many eggs in one basket.

'There are associated risks, including pressure on capacity constraints and the need to maintain teaching quality,' it said.

'There is also a concentration risk from reliance on overseas students from the same geographical location in the event of an economic downturn from that region.'

Even Sydney University Vice-Chancellor Michael Spence admitted in 2014 that they were 'over-dependent' on international students.

Some academics were more concerned about universities being undermined by foreign influence with so many Chinese studying there.

Charles Sturt University public ethics professor Clive Hamilton said Australia should admit many fewer Chinese students

Overseas student fees at Sydney University rose 92 per cent in three years from $391 million in 2014 to $752 million last year and 26 per cent to $560 million at UNSW

Some academics were more concerned about universities being undermined by foreign influence with so many Chinese studying there

The author of Silent Invasion: China's Influence in Australia said over-reliance on Chinese students was were 'corroding the soul of our universities'.

'University administrators walk on eggshells afraid to do anything that might antagonise the Chinese authorities. I find this deeply disturbing,' he told the Sydney Morning Herald.

La Trobe University China specialist James Leibold said universities were now also at the mercy of Chinese government political whims.

He said the Chinese Communist Party could easily respond to tension with Australia by discouraging its students from studying there.

'An obsession with growing the international student market risks turning our universities into diploma mills,' he said.

But researchers like Andrew Norton from the Grattan Institute said university bosses saw growing demand as an opportunity too good to miss.

'The universities are taking the calculated risk that, even if it doesn't last, the benefits are so great while it does last, that you should not forgo them,' he said.

A third of Australian international students were from China, but that figure was doubled at both Sydney University and UNSW

Overseas student fees at Sydney University rose 92 per cent in three years from $391 million in 2014 to $752 million last year and 26 per cent to $560 million at UNSW.

One in four Sydney University students now hail from China and international students now make up a quarter of its total revenue.

Across the state, universities now get more fees from overseas students than Australian ones - $2.27 billion to $1.99 billion.

A third of Australian international students were from China, but that figure was doubled at both Sydney University and UNSW.