A new beginning to policing in Northern Ireland will not be fully achieved until Sinn Fein is involved, according to the man overseeing reforms to the service.
A review of policing was a key element of the 1998 accord
Oversight Commissioner Al Hutchinson has urged Sinn Fein to join the Policing Board on Tuesday and will call on unionists to endorse the 50-50 recruitment arrangements.
The review of policing in Northern Ireland by former Hong Kong Governor Chris Patten was one of the key elements of the 1998 Good Friday Agreement.
Sinn Fein has boycotted the new policing structures, insisting the government's policing reforms need to go further if they are ever going to participate.
On Tuesday, Mr Hutchinson will publish his first report on the pace of change since he took over the post of Oversight Commissioner in December 2003.
Speaking on BBC Radio Ulster on Tuesday, Mr Hutchinson said it was important all political parties and community leaders "support this progress and change".
"The absence of Sinn Fein, for example... leaves a gap in terms of both accountability and progress.
"Equally, other parties have to support items like 50-50 registration of interest - so it is across the board.
"I am making the point that in the absence of full support, it will be an impediment to progress."
PSNI assistant chief constable Roy Toner, who is in charge of change management, said the areas of concern in the report were being addressed.
"Twelve months ago we were sitting here discussing the review of special branch - we have addressed that and are continuing to address that.
"You don't overhaul a police organisation of this size overnight. Patten said 10 years and we are three years into it at the moment.
"Fifty-four recommendations out of 175 are completed and 63 have made substantial progress - we are steadily on the road to achieving those changes."
The commissioner also reported that it would be next summer before an alternative to plastic bullets was available.
However, he said that neither the police nor the Army had fired one since September 2002, which he described as "a notable achievement".
The commissioner's office also has a plan which outlines how changes are to be implemented within the police Special Branch.
It will record the progress being made in its next report in September.
DUP Policing Board member Ian Paisley Jnr described the report as "uninspiring, predictable, Patten rhetoric".
"It is deeply disappointing that the Oversight
Commission has failed to address the real needs of the community, preferring instead to focus on nationalist hobby-horses, such as so-called human rights and 50/50 and the predictable call for Sinn Fein to join the Police Board," he said.
The Patten Commission said that an independent person should be selected to oversee the implementation of its 175 recommendations.
Mr Hutchinson, an officer with the Royal Canadian Mounted Police for 34 years, took over from Tom Constantine who held the position from May 2000 until his retirement at the end of 2003.