Green’s Dictionary of Slang

(N.Z. prison) to smuggle goods into/out of prison, thus tracker, one who smuggles.

1982		G. Newbold Big Huey 255: track (v) Smuggle contraband into and out of prison.
1984		B. Ellem Doing Time 198: tracking with me: refers to someone who is trafficking for a prisoner.
1990		Tupper & Wortley Aus. Prison Sl. Gloss. 🌐 Tracking. As in ‘tracking with me’ where someone has been organised to traffic drugs on a prisoner’s behalf. See ‘track.’.
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 193/1: track v. to smuggle goods in and out of prison [...] tracker n. a person who smuggles goods in and out of prison.
2006		B. Matthews Intractable [ebook] Fred worked a screw who agreed to track for us. For a percentage of the take the screw took our surplus tobacco stock out of the jail and on-sold it to a local tobacconist.