When Nathan Moss began podcasting his introductory psychology lectures last semester, he assumed no one was listening to them.

His classes stayed full and no one commented on the podcasts that he was taking up to six hours to prepare each week, until the time he was late putting them on the website. "I started getting all these emails saying, 'Where are the podcasts?"' said Dr Moss, a lecturer at Queensland University of Technology.

"It was really good because the [lecture] numbers weren't going down at all, so they were using them to revise," he said.

Podcasting has emerged as the latest innovation in university classroom teaching. Business and education lecturers are using it at Wollongong University, arts and medical lecturers are using it at the University of Sydney, and various disciplines are using it at Macquarie University, Newcastle University, the University of NSW and the University of Technology, Sydney.

UNSW started using podcasting this year through Lectopia, a technology developed by the University of Western Australia that is now licensed to 30 per cent of Australian universities. Lecturers request to have their classes podcast over the telephone and may provide PowerPoint presentations.

Students log in to use the recorded material on the internet and can download it onto an iPod or MP3 player.

The university introduced it for students with disabilities or poor English, only to discover other students were using it too, said Professor Tony Koppi, director of UNSW's Educational and Technology Centre.

At UTS the dean of education, Shirley Alexander, opposed a systemic rollout of podcasting on the ground that lecturers may limit interactive activities in class that cannot be recorded. "A lecture is not just a dissemination of information," Dr Alexander said. "Lectures can be and should be a lot more than that.

"[The US education thinker] David Thornburg said, 'Any teacher that can be replaced by a computer should be.'

"I would modify that and say any teacher that can be replaced by a podcast should be."