Rest breaks
Rest breaks are important to maintaining a safe workplace.
As a minimum standard you should receive at least one half-hour unpaid break for every 5 hours of work.
Most awards and agreements will also provide for 10 minute paid breaks during shifts of 3 or more hours in length on top of this.
Your boss should offer you your break. If they don't you should feel entitled to request it.
Working without breaks can lead to a loss in concentration and fatigue, and if breaks are denied consistently, this can lead to illness and an increased incidence of workplace accidents.
When taking breaks they should be genuine. You should not do any work during your breaks.