Meaning in very deep shit.

Expression from Victoria Australia, where there is a major sewerage treatment plant in an outer suburb of Melbourne called Werribee.

Thus any duck in Werribee is said to be in a hell of a lot of shit!

Obviously The name of Werribee can be substituted with the name anywhere with a large sewerage treatment plant or anywhere with large amounts of untreated sewerage.
by Captain Colvan March 4, 2012