This varies with economic conditions and Government requirements. There are not always short term opportunities but they still exist in the medium to long term.
As we are a fairly large organisation with thousands of staff there is a fair bit of movement in staff (e.g. people retiring, going on maternity leave etc.) which in turn can create an opportunity for someone to be promoted to their place. There are cases where people advance fairly quickly but most do so at a more standard speed. I believe that a lot of your ability to advance depends on what area of work you are in, timing, seeking out opportunities and a little luck
Every week there are job opportunities advertised at various levels throughout the Department. If you work hard in your graduate year and show you are capable of taking on responsibility, it won't take you too long to move up the ranks.
It is generally quite easy to get experience to advance, but the availability of promotions depends highly on the Government's stance on hiring.
There are promotion possibilities, especially for grads, as we are fast tracked to promotion through our training and development year.
I worked hard and won a promotion, however, I'm still doing work above my level which I haven't been rewarded for.