Justice Secretary Jack Straw is expected to receive a hostile reception when he addresses prison officers amid warnings of growing industrial unrest over pay.
Mr Straw will deliver a speech to the annual conference of the Prison Officers' Association (POA) which has already supported calls for industrial action.
Delegates voted earlier this week for an immediate work to rule, including turning up at jails at the exact start of a shift rather than earlier to change into uniforms, as is the norm.
The union warned that the action would start to affect prisons in England and Wales by the end of this week.
The POA is angry at a 2.2% pay deal this year following controversy over the Government's decision to stage a 2.5% wage award last year which reduced the value of the increase.
A POA spokesman said the 300 delegates at the conference in Portsmouth were angry with the Government over pay as well as a continuing ban on prison officers taking industrial action.
"It is clear they believe that New Labour has broken promises made to the POA and has reintroduced anti-trade union, Tory legislation, which is abhorrent."
Phil Wheatley, director general of the Prison Service, is also expected to receive a frosty reception when he addresses the conference before Mr Straw.
The POA official said prison officers were disappointed with Mr Wheatley for failing to support their case over pay, adding: "The feeling is that the Prison Service is being mismanaged and staff subjected to unjustified disciplinary action."
POA chairman Colin Moses said: "The employers and the Government have constantly abused the goodwill of staff throughout the United Kingdom."
