The Pharmaceutical Society of Ireland (PSI) has carried out a total of 270 "mystery shopper" visits on pharmacies around the country to ensure that strict new restrictions on the sale of products containing codeine are being properly enforced.

The visits, which typically involve individuals posing as customers looking for pain-relief products such as Nurofen Plus or Solpadeine, were conducted since the start of August when new guidelines for the sale and display of the products came into effect.

But despite resentment among some people at being quizzed when they looked to purchase these over-the-counter drugs, the society said it had not received any formal complaints about the guidelines to date.

The PSI, which is the regulator for pharmacies in Ireland, also carried out 112 more formal pharmacy inspections during that time.

Under the new PSI rules, pharmacists have to ensure customers know how to use such medicines properly.

As a result, codeine medicines such as painkillers and cough bottles must only be supplied under the personal supervision of a pharmacist, who must advise customers that the products only be used when considered necessary and for the shortest time possible.

"The PSI has carried out 112 pharmacy inspections/visits between 1 August and 31 October… The number of 'mystery shopper' visits carried out in the same period was 270 and again compliance is checked as part of these visits," a spokeswoman for the PSI said. "During August, the 'mystery shopper' system reported two instances where it was believed the guidance was not fully met. In both cases we took action to effect compliance."

The Sunday Tribune recently revealed that sales of codeine-based products had almost halved since the new rules took effect, as customers moved towards other types of pain relief.