The Justice Minister Frances Fitzgerald is refusing to speculate on the contents of a report, advocating major reform of how the garda force is organised.

The shake-up could see new regional units replace national crime units and has been put together by the Garda Inspectorate.

It followed an inquiry into claims from whistleblowers that certain crimes - including murder and rape - were not properly investigated.

Ms Fitzgerald says she will comment publicly after she presents the report at Cabinet in the morning.

The report is expected to strongly criticise the existing policing model and procedures.

It is also expected to call for new serious crime squads in each of the garda regions, as well as giving individual superintendents control of specific tasks - such as traffic - in each area, rather than overall control.

Already, senior gardaí fear the report could mean cuts to the number in the upper ranks of the force.

These changes could have a major impact on Dublin-based national units - some of which may be decentralised.