Five Australian universities have made the top 50 in the latest league table of the world's best institutions, but the majority of institutions have failed one important measure.

Australian institutions performed well for their academic reputation and international student ratios in the QS World University Rankings. Most, however, were at the bottom of the list of 1000 universities for their staff-to-student ratio.

Australian National University is the country's top-ranked institution in equal 29th place. Credit:Louise Kennerley

Australian National University is the country's top-ranked institution in equal 29th place, a small fall from 24th last year. It was followed by the University of Melbourne in 38th place, the University of Sydney, 42, the University of NSW, 43, and the University of Queensland, at 47.

Monash University, 58, and the University of Western Australia, 86, have also appeared in the top 100.