The Commercial television industry code of practice has rules about how much non-program matter (including ads) is allowed each hour. This is in section 5 of the code.
Community radio and TV
Community radio and TV stations are not allowed to broadcast ads. Radio stations can broadcast sponsorship announcements for up to 5 minutes each hour. TV stations are allowed 7 minutes every hour for these announcements.
Community broadcasting sponsorship guidelines help broadcasters understand the rules around these announcements.