Green’s Dictionary of Slang

a milkman.

1911		Truth (Sydney) 2 July 1/3: The floods in Melbourne have proved the salvation of the cowjuiceries, for dairymen now aver that the water got into the milk. Ooray, for the milkies!
1914		Sport (Adelaide) 17 Apr. 4/6: Bob M, the turned down milkie, has started a goat milk round.
2003		‘An Adventuring Life for Me! (by the members of Sendero Luminoso)’ Crasimoff’s Quest World ‘Crasimoff’s Chronicles’ Issue 204 🌐 They heard the cheery whistling of the man who brought fresh milk to town. It was a homely sound, one that made them feel secure. Then the whistling stopped as the milkie shouted, ‘Mornin’ love.’.