CLOSE to 1000 teachers at Australia's top university are being told to make their students happy at the expense of confronting their fledgling thinkers with rigorous lessons, says the union representing lecturers.

Teachers at the Australian National University now need to explain themselves if too many students are not pleased with them and colleges must argue why courses with student satisfaction rates less than 50 per cent should be kept.

Teachers at ANU will have to explain themselves if students are unhappy with their work.

Students have for years been asked to fill out satisfaction surveys at the end of each semester. But the university's education committee earlier this year decided to assign them greater importance by strongly linking them to teachers' performance reviews.

In the past fortnight, numerous teachers have been asked to explain why students have given them poor marks for the first semester.