For a significant number of Australian males to have a crashing hangover is to be respected, to be able to drink vast quantities well beyond the call of thirst is commendable, to 'chunder' this unnecessary liquid is hilarious, and to collapse paralytic on the floor from intoxication is magnificent. If conditions allow a fight then the ultimate plane has been reached. It is all part of the ocker syndrome and heavy drinking is much more important than sexual prowess. 

Jonathan King, Waltzing Materalism, 1976

The talented comedian Ron Frazer appeared in a series of TV sketches from which I retain a mental picture of him leaning on a bar, speaking with a broad Australian accent, probably wearing shorts and thongs, and periodically sinking a glass of beer. As that character was called 'Ocker', ocker became the name of the type

Gerry Wilkes, Exploring Australian English

The new Australian boorishness is known as Ockerism, from a slob-like character called Ocker in a television series - the embodiment of oafish, blinkered self satisfaction.

Expatriate poet Peter Porter, 1974, as quoted in The Ugly Australian.

Once again, the previous quotes paint a very discriminatory and unfortunate picture of Australian culture (as did the Australian Government in the fiasco regarding Norm, who is no doubt a blood relative of the ocker). Regardless of the words origin (which, surprisingly, is a recent one), the modern meaning of the word is not as pejorative as those quotes would indicate.

Australian women, women in the land of mateship, the 'Ocker', keg-culture, come pretty close to top rating as the 'Doormats of the Western World'

Miriam Dixson, Historian, University of New England, 1976

It is true that when someone claims, "He's a bit of an ocker", Australians do immediately form a picture of a very Australian character: A bloke who is a bit rough around the edges, who enjoys his beer, loves his sport and demonstrates all of the stereotypical Australian traits. Ideally, he would be wearing a singlet, and a pair of stubbies. He would speak very slowly, and use a lot of Australianisms (many of which were offensive).

But again we stress, this isn't necessarily a bad thing. 

Take a break from drinking like the author of this article did - Read why and how in his book Between Drinks: Escape the Routine, Take Control and Join the Clear Thinkers