Green’s Dictionary of Slang

(S.Afr.) a general term of abuse, esp. of a police officer.

1975		S. Roberts Outside Life’s Feast 88: ‘Bladdy vark!’ she said bitterly. ‘Rubbish, that’s what you are.’.
1986		D. Case Love, David 41: There is only one thing that he really loves and that is his bottle. The vark has a cheek to tell you that! [DSAE].