Green’s Dictionary of Slang

(Aus.) a venereal disease clinic.

1924		(con. WWI) A.G. Pretty Gloss. of Sl. [...] in the A.I.F. 1921–1924 (rev. t/s) n.p.: blue light. A prophylactic establishment.
1954		(con. 1940s) T.A.G. Hungerford Sowers of the Wind 28: We don’t want to get jacked-up, that’s what [...] We got no blue-light outfit with us.
1990		R.G. Barratt ‘Who’s Jack of Robbo?’ in What Do You Reckon (1997) [ebook] I got the jack years ago and had to go to the VD clinic [...] the old blue light.
2000		Desdemona at www.asstr.org 🌐 Mama always said: some men weren’t worth pleasing. And a man with stock in the blue-light clinic was one of them.