Prison officers have voted two-to-one in favour of a new deal on working practices in Northern Ireland.
The introduction of new custody officers and simplification of senior management structures is part of a package of reforms governing relations in jails.
Justice Minister David Ford said agreement on the new working arrangements was reached in March between management and Prison Officers' Association (POA) union leaders.
"This historic outcome heralds a new era of industrial relations within our prisons and allows for the fundamental reform programme to modernise the Prison Service to continue apace," he said.
The association balloted its members and the union informed the Prison Service that by a majority of two thirds, prison officers have endorsed the new package.
Agreement was reached after months of detailed and painstaking negotiations.
Included in the arrangements is the replacement of the long-standing framework agreement with a new staff deployment agreement, a new operating model for prisons launched with appropriate staff-to-prisoner ratios and a new core day and an introduction of new custody officer and offender supervisors roles.
More than 150 staff left at the end of March under the service's exit scheme and the endorsement by the POA membership of the new working practices means that more will be able to go when it is operationally possible.
Almost 5,000 applicants were received for the new custody officer roles and after the first part of the recruitment campaign, 900 candidates are now going through the assessment centre with the first new recruits due on the landings before the end of the year.
Mr Ford said: "Reform of the Prison Service is unstoppable. While much has been achieved over recent months there is still much more to do and I am determined to maintain the momentum of change."