Garda Commissioner Martin Callinan has said the number of gardaí on duty has been increased by as much as 25% at certain times of the day due to a new roster system.

Mr Callinan said that a new garda working time agreement had been developed and implemented with the agreement of the garda associations.

He said it was significant because it is the first time that rosters and working times have been changed in over 40 years.

The Commissioner also said the aim now was to match the availability of gardaí and resources with the policing needs of the community, while at the same time protecting the welfare of gardaí.

The new rosters, which ensure there are more gardaí on duty at busier times, have been implemented at no additional cost.

They also allow for shifts to overlap and for greater flexibility by changing shift start times to coincide with the policing of major events, investigations and court appearances.