Green’s Dictionary of Slang

1. of humans or objects, an extremely inferior example; also attrib.

1898		Truth (Sydney) 13 Feb. 6/6: [T]he wobbegong wofflings of a person of the name of Heydon, who has wandered around the Russia-China kick-up with a pen dipped In a mixture of red ink, sentiment, and Imperialistic jingo syrup.
1904		Truth (Sydney) 10 July 5/3: Then the weary, woebegone wobbegong worried himself into a mild spasm of excitement over the ‘fact’ that a Yellow-belly candidate had been adopted.
1991		R.G. Barratt ‘A Tour de Bondi’ in What Do You Reckon (1997) [ebook] [T]o get this wobbegong together would mean moving down there.
1999		R.G. Barrett Wind & Monkey (2013) [ebook] ‘Fuckin oath. She’s an old wobbegong’.
2000		R.G. Barrett Leaving Bondi (2013) [ebook] Les was curious why she, or anybody else, would invest in a Z-grade wobbegong like Leaving Bondi.

2. anything excellent or outstanding.

1919		Mirror (Sydney) 23 Mar. 5/6: [of human swimmers] The latter are quite touchy on the point taken by their opponents that several years of droughts in the Holy Land have put them out of running with the wobbegongs from the Somme.
1940		Dly Telegraph (Sydney) 19 May 14/5: [...] whop-cacker, wobbegong, pearler, purter, bonzo, rlpsnorter, snodger, snozzler [...] All of these words imply excellence or notability.