The Competition Authority has raided the offices of the Irish Pharmaceutical Union (IPU), the representative body for pharmacists.
It is understood the move formed part of an investigation announced several weeks ago by the authority following the controversial decision by a number of pharmacists in the Dublin region to withdraw from the methadone provision scheme as part of a row with the Health Service Executive.
In a statement yesterday the pharmacists' union said it could confirm that its offices had been visited on Thursday by representatives of the Competition Authority.
"The HSE and Department of Health and Children are currently in dispute with the IPU over the right of pharmacists to be represented by their trade union on the negotiation of remuneration arrangements with the State authorities.
"The IPU has fulfilled this role without dispute for over 35 years", it said.
The Competition Authority did not comment.
It is understood the authority is examining some documents it obtained at the IPU offices.
In October, the authority visited about 15 pharmacies in the Dublin area as part of its investigation into whether pharmacists who had withdrawn from providing methadone to recovering drug addicts were breaking the law.
Staff from the authority, accompanied by gardaí, served summonses on the pharmacists to appear before an inquiry it was carrying out. Under competition law, the organised boycotting of such schemes is regarded as being in breach of the Competition Act.
In October about 140 pharmacists withdrew from dispensing methadone to about 3,000 recovering drug addicts.
This action was in protest at the decision of the HSE to cut the mark-up paid to wholesalers for drugs which are dispensed by pharmacists under the medical card scheme.
The pharmacists claimed this would make the dispensing of drugs by them to medical card holders a loss-making exercise.
They also expressed anger that the Health Service Executive (HSE) would not discuss the fees they get paid with their representative body, the IPU.
The HSE said at the time it accepted that the remuneration structure for pharmacists was "unbalanced" and it was committed to addressing this.
However, it claimed that to discuss fees with the IPU would be in breach of competition law.
The pharmacists argued they were not breaking competition law by withdrawing from the methadone scheme.
The HSE's planned reforms of the payment system for drug wholesalers, which were scheduled to come into effect at the beginning of December, were later deferred.
Taoiseach Bertie Ahern said this was to allow a mechanism to be reached to establish a community pharmacy contract.
However, HSE chief executive Brendan Drumm told the Oireachtas health committee recently that every month the new pay rate was delayed would cost €8 million.