Depending on the position, elections are held every 2 or 4 years.  

All members are advised when union elections are approaching, and everyone can nominate for a position who is eligible.  For example, if the position if for a casual representative in a particular Branch all casual members who are from that Branch are eligible to nominate but not casuals from other Branches or people who are not employed on a casual basis. If it is a National Salaried Officer position, any member can nominate. 

To find out more about NTEU elections go to the NTEU Rules