It also has concerns over trainee gardaí with no driver training
The Policing Authority has criticsed garda management for not implementing recommendations from the Garda Inspectorate.
The authority says 33% of recommendations from the 'Changing Policing in Ireland' (CPI) report are classified as 'not commenced' or 'under review'.
It also says that 50 recommendations were marked as complete - but this was not the case.
It says: "It became apparent that a number were not and this prompted the authority to seek further evidence.
"The authority is satisfied to mark nine as complete at this time.
"This apparent uncertainty as to what is meant by complete calls into question the reliability of the Garda Síochána’s reporting and the level of coordinated internal oversight of the MRP (Modernisation and Renewal Programme) process."
It also says that while the Garda Síochána has clarified who is responsible for the implementation of each of the recommendations, no reporting has been received by the Policing Authority which gives assurance that there are structures in place.
The authority says the slow uptake in implementing recommendations "suggests that a significant proportion of the recommendations do not yet have visibility within the change programme."
An Garda Síochána has expressed confidence that the change programme will be delivered in the five years as planned.
But the authority says, one year into the programme, it has yet to be assured "as to the basis for that confidence".
However the report did welcome that there has been good progress on putting elements of a risk management architecture in place.
But it says the employment of a full time civilian risk manager should be prioritised over the coming months "to enable an effective risk management system to be fully established in compliance with good governance".
The authority is also concerned that trainee gardaí continue to leave Templemore without driver training.
It says this is worsening a backlog of driver training to be completed.
The report also adds: "The absence of a strategy for the Garda Reserve combined with an uncertainty as to how many reservists are active is of concern to the authority.
"At a time when the composition and structure of the service is changing, through greater numbers of civilians and the roll out of functional policing, it is concerning that a vision and strategy for the role and deployment of the reserves in this context is not developed."
The authority has identified a number of actions it will take in the coming months, including:
The report comes just days after Noirin O'Sullivan retired from her post as Garda Commissioner.