He said that, in consultation with the local GP, he gave the addicts a week's supply of the heroin substitute so they would not be without it during the action. He explained he did not think the pharmacists' action would last longer than a week and added he was aware of other pharmacists in Dublin who had done likewise.

However, Tony Geoghegan of the Dublin drug treatment centre, Merchants Quay Project, said even if the pharmacist was trying to limit the effects of the industrial action on addicts, it was potentially dangerous. "Of the 3,000 recovering drug addicts on the methadone programme, no more than 20% would have advanced far enough to be trusted with a week's supply, " he said yesterday.

Most addicts are prescribed a daily dose of methadone which must be taken on the pharmacist's premises, Geoghegan said. "The danger in giving a week's supply is the addict may consume the methadone in two or three days, or pass it to a friend, leaving the addict without any treatment for a number of days. This could force the addict out into the black market with destructive consequences."

The pharmacist stressed he had consulted the GP about issuing a week's supply. He also said that, as the dispute enters its second week, he will not be doing the same this week and has instead referred all addicts to the local HSE clinic. He added that this was likely to put further pressure on the 13 centres the HSE set up to dispense methadone to the 3,000 addicts who can't get it at their local pharmacy.

A HSE spokesman this weekend said that, while staff at the centres were coping, they were "overstretched". Geoghegan said he was "disgusted" at the pharmacists and the HSE for using such a vulnerable group who were trying to get off heroin "as a wedge in a dispute over money".

Exploratory talks between the Irish Pharmaceutical Union and the HSE, under the mediation of Bill Shipsey BL, ended last Tuesday without agreement. The HSE said the pharmacists will have to call off their action before any consultations can begin on pharmacy fees.

But it added that the decision to halve the pharmacists' mark-up could not be changed, saying it would save the health service 100m a year.