how much time will DIAC on average will take.....if you have passed your TRA, IELTS with 7 band, medicals cleared.......and satisfy police requirements too.....

profession is cook.

on average 6 months.....

I could say meatdd, a parallel could be my spasmodic satellite internet service at the moment with a lot of variables affecting my ability to get a reliable connection at the specified speed.

I recall last time you posted that you stated you had done a state nomination application and if that is so it ought to help within the new processing priorities system.
But there'll still be a few variables:
. staff coming back from main Xmas break
. existing workload to be completed
. management working out just how new priorities will be applied to day to day flow
. they'll probably run training courses for staff
. The governement [Big Brother] may actually be doing all they can right now to make the process slow down even more given the worsening of the economic outlook - perhaps even a monthly quota applied!

You could try contacting your CO and see what update you can get.