A Muslim student has described the "frightening" experience of finding a pig's head near a mosque at a Western Australian university just before his traditional midday prayer.

University of WA PhD candidate Majdi Fal was working in his office on Sunday morning before taking a lunchtime break, he told Radio 6PR on Monday.

He then went to complete his regular prayers around 12.40pm and stopped at the bathroom first.

He had taken off his glasses, so when he first saw stains on the floor he thought they might be dirt. He then realised they were blood, and thought for a moment it was human blood.