The majority of sliotars used by the GAA are made in Pakistan and China, in breach of association rules which state that Irish companies must be used in the manufacture of playing equipment.

According to sources in the industry, the sliotars can be imported for one-third of the price it would cost to manufacture them here.

All of the balls are subjected to a standard test in Dublin City University, whatever their origin.

The GAA's official guide, last revised in June this year, states: "The association shall support Irish industry. All trophies and playing equipment shall be of Irish manufacture. Penalty for non observance €200."

The director of games at Croke Park, Pat Daly, denies that the importing of sliotars breaks the rules.

He was non-committal on the above rule, which is number four of the general aims of the official guide.

"We live in the real world. Times change," he said. "Most of manufacturing has migrated abroad."

Most sliotars, almost certainly including those which will be used during today's All Ireland hurling final, are manufactured in the Pakistani city of Sialkot, although some are made in China.

A child labour scandal in Sialkot 10 years ago resulted in increased monitoring of work practices, but there is little monitoring of practices in China.

A whole range of manufacturing companies in Sialkot now advertise making sliotars and include images of intercounty hurlers on their websites.

One company contacted by this newspaper supplied detailed specifications for a whole range of sliotars. Arslan Brothers provided a list of 12 different types of sliotars which it makes, in different sizes, cores and types of leather.

Most of the companies and agents on the GAA's list of approved suppliers confirmed that they source the balls abroad, mainly in the far east. Out of the 12 approved suppliers – all of which are listed as "manufacturers" – only three make the balls in Ireland, according to a survey conducted by this newspaper.