I am travelling next week to Hong Kong and Taipei on CX with a CX ticket.

I am travelling next week to Hong Kong and Taipei on CX with a CX ticket. I have recently lost my QF gold status, down to Silver. I do have some QF lounge passes, but from what I can see I will not have any lounge access leaving Melbourne - is that correct? I have a credit card that gets me into Veloce lounges in Asia, but there is not one in Melbourne.

It depends on the conditions on those passes.  If they say Qantas, Jetstar and Emirates (as I believe the more recent ones do ) then you are out of luck.

Australian airports generally don't have many third-part options (like Priority Pass or Veloce)

The United lounge at MEL can be accessed if you're with Priority Pass...

QF lounge passes are only valid on a QF or JQ flight number in QF operated lounges

I thought so. Thanks.