Summary Offences Act 1981, s 11B
It’s a criminal offence just to have things like spraycans or markers in your possession, if you don’t have a reasonable excuse and if someone could reasonably conclude at the time that you intended to use them for illegal tagging or graffiti. In these situations you’d need to convince the police, or the judge if it goes to court, that you had the cans or markers for a legitimate purpose – painting a mural for a school or community project for example.
For this offence you can be sentenced to community work, or fined up to $500, or both.