I want to visit Hong Kong for two days I'm permanent residence in Australia

Since you have Pakistani passport, you still need to apply for a visa to visit HK.

Hello ,
Could you please let me know how did you apply visit visa for Hong Kong and how long did it take to get the approval ???

You should first prepare the required documents: copy of your passport, a completed application form, a half-length color photo, hotel reservation, flight itinerary, proof of financial standing, and travel plan.
If you submit the application to the embassy of PRC and it is dealt with there, 4 working days are needed, but the application is transferred to HK immigration department or you mail your application there directly, 4 to 6 weeks are needed.