Former ACT Chief Minister Jon Stanhope has targeted Justice Minister Shane Rattenbury in a scathing critique of government inaction over the territory's prison needle exchange program.

The program, designed to stop inmates sharing dirty needles behind bars in a bid to curb the spread of diseases, was a key element of the Labor-Greens 2012 parliamentary agreement.

Justice Minister Shane Rattenbury, who blamed the stalled initiative on former chief minister Jon Stanhope. Credit:Alex Ellinghausen

Prison guards have been strongly opposed to needle exchange programs in the past and comprehensively voted to reject a proposal in 2016.

Mr Rattenbury blamed inaction on what he said was Mr Stanhope’s decision in 2008 to give the Community and Public Sector Union a veto over the program via a clause in guards’ enterprise agreements.