Judith Collins' 'Crusher' nickname comes from her boy-racer policy but also feeds into her self-styled image as Govt hardwoman.

Tough decisions about prisons, education, pensions and tax need to be made if NZ is to avoid a looming Government debt crisis, says Treasury.

Corrections has threatened that existing prisons will be fast-tracked into private management unless guards agree to prisoners 'double-bunking'.

A Facebook page set up by prison officers to vent their anger could now get them fired instead.