Green’s Dictionary of Slang

a dock labourer.

1937		in E. Raymond Marsh in DSUE (1984).
1958		C. Lee diary 4 Sept. in Eight Bells & Top Masts (2001) 154: The dockies are on strike. Want bigger rice bowls or something.
1984		V. Darroch On Coast 146: Dockies: Diminutive/nickname for painters and dockers.
1991		M.B. ‘Chopper’ Read Chopper From The Inside 48: This was a dockies’ pub and the onlookers were a pretty critical audience.
2005		M.B. ‘Chopper’ Read Chopper 4 121: It’s a good thing he didn’t get down to [...] a dockies’ pub and bung on an act.