I hold a Sri Lankan passport traveling to New Zealand in transit at Melbourne, Australia. I have a New Zealand work visa. Do I need to get a transit visa in Australia for 5 hours in transit?
As a Sri Lankan citizen you are not eligible for Transit Without Visa (TWOV) in Australia. You should apply for a Transit Visa Subclass 771 which allows you to stay in Australia for up to 72 hours. The good news is, it's free!
You'll find all the details, including how to apply, on the page I link below.