If you have been released on court or Police bail and you do not turn up for your next court appearance as required, a warrant can be issued for your arrest (for bail generally, see How to obtain bail).
Further, failing to turn up at court in this way without a reasonable excuse is a separate offence. If you had been released on court bail, the offence is punishable by up to a year in prison or a fine of up to $2,000; in the case of Police bail, it is punishable by a fine of up to $1,000.
This offence is separate from and in addition to the original charge that your bail related to. Therefore you can be convicted and sentenced for failing to appear in court even if you are found Not Guilty of the original offence.
If a Police officer has reasonable grounds to believe that you won't turn up at court or that you have breached any condition of your bail, the officer can arrest you without an arrest warrant (for conditions commonly imposed with bail, see How to obtain bail).
The Police will then bring you before the court and oppose a new bail on the grounds that you have breached the original terms of the agreement. If the court is satisfied that you had absconded or were about to do so, or that you had breached the conditions of your bail, then it must reconsider your bail and will be unlikely to allow you to remain on bail.
In particular, the court will look at the seriousness and nature of the original offending and compare it with the circumstances or conduct that was involved with your bail breach â€“ for example, if you were originally charged with a burglary in the early hours of the morning and you are caught walking the streets at similar hours in breach of a bail curfew, the court won't take kindly to another application for bail.