The Oxford one-to-one tutorial is being eroded to allow academics more time to do research.
Group seminars of up to ten students have already replaced some tutorials in economics and are being piloted in law, psychology, politics and philosophy.
A spokesman for the university said: "The tutorial is not being completely phased out but the number of tutorials is being reduced. This has happened in economics without any damage to quality."
He said that allowing academics more time to do research benefited students by bringing them into contact with academics at the cutting edge of their disciplines. "It is in the interests of the whole academic community to allow more time for world-class research," he said.
Many of the group tutorials were also being given by graduate students.
"We find that graduate students benefit from the teaching experience and, again, there is no evidence that this is detrimental to the students," the spokesman said.
But a spokeswoman for the students' union said: "We have had a number of complaints from students in these areas at the loss of the tutorial. If this is a cost-cutting measure then we are concerned. We understand the need to free academics to do more research - but this must not be done at the expense of the undergraduate experience."
She said that many students had a positive experience of being taught by graduates. "But if the university is going to move towards greater use of graduates as tutors, there must be proper training," she added.
* The Oxford University Constables, who have policed undergraduates for nearly 800 years, are to be disbanded and will hand in their warrants later this term. The constables are being renamed proctors' officers and will continue to steward events. They will trade in their trade-mark bowler hats for uniforms similar to those of Thames Valley Police.