Green’s Dictionary of Slang

(Aus.) New South Wales; also attrib.; thus ma stater, a native of New South Wales.

1906		Bega Budget (NSW) 20 Jan. 4/1: [headline] The Sore-headed ‘Ma’ State [...] Don’t try to create an impression that New South Wales is being taxed for the benefit of the other States, or is carrying the burdens of the other States. You know perfectly well that New South Wales, like any other State, gets back its own surplus, and spends it on itself.
1910		Bulletin (Sydney) 22 Sept. 36/1: He bored so well that he punched a leak into the largest underground tank in the world. Straightway the Ma State, the Banana State, the Holy State, and Messrs. Jumbuck, Horny & Co. all started punching hundreds of holes into that big tank. [Ibid.] 24 Nov. 10/1: The Ma State railways have lately been making some interesting experiments in train-coasting.
1914		Bulletin (Sydney) 22 Oct. 13/1: I forgot the Sydney people – / I forgot the big Importers – / I forgot the little Geebungs – / I forgot the Ma-State-Frighters!
1924		Truth (Brisbane) 17 Feb. 8/4: [headline] Lady Champions Display Their Prowess. Mermaids From the Ma State.
1936		Sydney Sportsman 14 Mar. 5/4: Ma State Losing any Mokes. [...] the rate at which pacers and trotters are being transferred from New South Wales to other States is increasing rather than diminishing.
1941		Baker Popular Dict. Aus. Sl.
1955		N. Pulliam I Travelled a Lonely Land (1957) 70: New South Wales [...] good naturedly called the ‘Ma State.’.