Green’s Dictionary of Slang

maxi n.2

(N.Z. prison) constr. with the, life imprisonment.

[NZ]D. Looser Boobslang [U. Canterbury D.Phil. thesis] : .

In compounds

maxi block (n.)

(N.Z. prison) solitary confinement or punishment cells.

[NZ]D. Looser Boobslang [U. Canterbury D.Phil. thesis] 115/2: maxi block n. the area of the prison that contains the short-term solitary confinement punishment cells.
maxi seps (n.) [‘Inmates on maxi seps get locked down for 23 hours a day, with one hour's exercise’ Looser (2001)]

(N.Z. prison) maximimum separates, an extra level of isolation for an inmate who still causes trouble when in segregation.

[NZ]D. Looser Boobslang [U. Canterbury D.Phil. thesis] 115/2: maxi seps n. pl.

In phrases