Officer uniform?? Need help with ID

[Jeffweil]

Any information on shoulder patch would be appreciated
American collector
Shirt looks to be private purchase - has leather button? Holes on shoulder strap for pips - need to get some to complete. Australian stuff is rare here in US - just got these 3 pieces from collectors estate. Took him 40 years to find these 2 uniforms here
Any information on shirt or patch would be appreciated