donko, n. — Green’s Dictionary of Slang

donko n.

[? synon. N.Z. SE donkey room, orig. (1920s) the enclosure on the Wellington docks where a donkey engine was kept and at the time was the only warm shelter available]

(N.Z.) a room set aside in the workplace for smoking, relaxation etc.

1976		R. Morrieson Pallet on the Floor 53: Hastening [...] up the stairs to the ‘donko’ to wrap the sacking known as ‘sneakers’ around his boots; going down these same old slippery stairs from one of the freezing chambers.
1984		Listener (NZ) 14 Apr. 13: In the woolstores [...] smoko was held in the donko, where we’d adjourn after working like billyo [DNZE].