The Transport Minister Troy Buswell has denied claims the safety of passengers on Perth's trains is being compromised.

A report has revealed more than a third of Perth's train drivers who took part in a survey have fallen asleep at the controls because of fatigue.

Mr Buswell says safety devices on Perth trains are among the best in the world.

"For example, the vigilance devices, which ensure that the drivers are active and the automatic train protect devices, that ensure, for example, that if a train goes through a red light at speed, the brakes are automatically applied," he said.

The findings come amid scrutiny that the metro rail system is at capacity.

The ABC has obtained a copy of a report completed last year for the Public Transport Authority in which 124 Perth train drivers were surveyed.

While 64 per cent said they never fell asleep at the controls, 33 per cent admitted they had done so on occasion and three per cent did so regularly.

A driver who took part in the study by the University of South Australia has told the ABC one of the biggest issues for drivers is pressure to meet unreasonable timetables.

Labor's transport spokesman Ken Travers said earlier that the State Government must deal with the issue immediately.

"I don't think people in Western Australia would be getting on the trains if they thought that there's a possibility that the driver might fall asleep," he said.

"The Premier should be putting this at the top of his list - fix the public transport."