More and more people are keeping roosters in their backyards. Lots of us love the sound of a crowing rooster, but not everyone. Most of us that do keep roosters lock them up in a sound proof box over night and let them out at a reasonable hour. No one likes being woken up at 3am.
Below are some useful links on the subject.
Link to section of noise laws that state the animals are exempt: http://www.edo.org.au/edoact/factsheets/FS11noise.html#cover
"The Environment Protection Act 1997 (the Act) and the Environment Protection Regulation 2005, aim to protect people from undue noise whilst enabling them to carry out business and social activities. This legislation does not apply to noise generated by aircraft (including hot air balloons), cars on public roads, animals and people (e.g. rowdy behaviour)."
So, basically, there is no decibel limit for animals (however this doesn't mean that your rooster can get away with crowing 24/7).
There are animal nuisance laws, which rooster complainants have to follow. The page contains a link to the steps for lodging a complaint: http://www.tams.act.gov.au/live/pets/keeping_dogs_in_the_act#nuisance
The process of lodging a complaint in regards to a noisy animal is well set out and is far from a walk in the park for the complainant.
And some of the animal welfare legislation: