There have mainly been attempts, none successful, to convert regions of certain Australian States into new states.
There have been several people who have attempted to start secession movements, such as rich individuals in WA who rant about 'all the minerals income going to the feds' - when you think about this you realise that WA has a negative balance of internal trade - the trains carry loaded containers west and return empty. So secession becomes a bit useless.
The most recent trend has seen both the ACT and NT decide to remain as territories rather then become states because of the large financial support they get from everyone else.
Statehood for these two may have become a pain if the additional senators had unbalanced the Senate one way or the other,