5 Australian universities cracked the world's top 50 ranking this year. Here's who made the cut.

• Five Australian universities have nabbed a spot in the top 50 global rankings this year.

• The Australian National University was again crowned the country's top institution, coming in tied at 31st.

• The rankings come as inflows of international students – and especially Chinese students – are at risk, raising questions over the sustainability of current student fees and the research teams they pay.

• Visit Business Insider Australia's homepage for more stories.

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Australia's universities have again batted above their average, retaining their place in this year's global rankings.

Despite falling two places, the Australian National University (ANU) again took out Australia's top post, ranking 31st and tying with London's King College and Montreal's McGill University in the 2021 QS World University Rankings.

University of Sydney's hallowed halls improved by the same margin to rank 40th and just beat out the University of Melbourne at 41st.

Rounding out the top 50 was the University of New South Wales and the University of Queensland, placing 44th and 46th respectively. They were followed by Monash (55th), University of Western Australia (92nd), University of Adelaide (106th), UTS (133rd), and Wollongong (196th) in the top 200.

However, while the country's tertiary education sector might celebrate the plaudits, it comes at a difficult juncture for the universities themselves. Most excelled when it came to internationalism –which in turn helped buoy their overall scores – but it now may be threatened as Chinese students are warned from attending Australian institutions.

If those students were to heed their government's warning it would threaten to turn off a $12 billion student fees tap, which has helped Australian universities, in turn, pump money into research and help institutions climb the rankings.

"While spending that money on research may make universities look good, it really does very little for the classroom experience," University of Sydney associate professor Salvatore Babones told Business Insider Australia.

"The universities that have gone the whole hog on international students have marched up the research rankings by buying international research teams in areas of high impact research. It's nice for rankings but it doesn't really make any difference to your ability to educate students."

One metric that continues to be in decline is teacher-to-student ratios. Thirty-four of Australia's declined in this respect in the last 12 months according to the rankings. Instead, larger class sizes have been met with a string of staff and course cuts at universities around the country as a result of the COVID-19 pandemic.

The University of Sydney cut close to 10% of its arts and social sciences courses in May, according to the Sydney Morning Herald. RMIT, La Trobe and Deakin University meanwhile laid off hundreds of "non-essential" staff, while hundreds more at Monash could soon follow.

It could see some of Australia's most prominent universities which depend on international students, struggle to maintain their strong rankings in coming years.

Elsewhere on the list MIT once again took out the number one spot for a record-breaking ninth year in a row, with Standford, Harvard, Caltech and Oxford rounding out the top five. The United States and the United Kingdom continued to dominate the rankings, collecting 43 of the top 100 spots between them.