entering a public or private place in a way that will cause a breach of the peace or reasonably could breach the peace.
(section 9(1)(g) of the Summary Offences Act 1966 (Vic)).
Some examples are:
Using a megaphone to make a speech;
Playing music over a loud speaker;
Yelling and chanting.
During protests and rallies, breaches of the peace are often tolerated by police. But it can be used unexpectedly when good favour with police changes. See more about police tactics at protests.
The maximum penalty 25 penalty units or 6 months’ jail.