To back this up - I went through the oral exam experience on both sides (student and TA) with two different German professors and it worked incredibly well. We offered oral exams as a remedy for a few situations:

- suspected/known cheaters - students who missed exams due to illness - times in the course where we needed to get a good grip on whether our students understood the coursework the way we'd taught it

It was scary for a lot of students, especially the ones without great English, but it was always, in my view, incredibly fair.

edit: based on your comment history you're also in Australia - I have a feeling we might be talking about the same place :)