Ninety prison visitors have been arrested on suspicion of smuggling drugs into prisons so far this year.

The arrests follow the introduction of new measures including the establishment of a confidential phone line to tackle drug abuse in the prison system.

Over 600 drugs parcels have been intercepted and more than 430 homemade weapons seized from inmates. A total of 470 phones have been seized so far this year.

More than 140,000 people have visited inmates in prison since January, of which 90 were arrested on suspicion of drug smuggling.

The Irish Prison Service said some were apprehended after a call was made to its confidential phone line.

It also said drugs are the cause of much of the violence in prisons.