The National Lottery watchdog has said the proportion of retailers not properly implementing rules to prevent young people purchasing lottery products "remains unacceptable".
The Office of the Regulator of the National Lottery (ORNL) said while "significant progress" has been made on the issue, "more needs to be done."
Last year, the ORNL commissioned its second underage mystery shop, to examine the retail sector's compliance with rules governing the sale of National Lottery products to under 18s.
It followed a similar exercise in 2018.
The findings, which are contained in the regulator's annual report for 2024, show that that 72% of the mystery shoppers were denied a sale when attempting to buy a €1 scratchcard.
It compares to a figure of 62% during the previous survey.
71% of the retail outlets challenged the young shoppers, up from 63% in 2018.
The number of retailers displaying the mandatory "18+" signage also increased, from 73% to 92% in 2024.
The test purchasers, who were boys and girls aged between 15 and 17 years old, visited 562 retail premises, as part of the research carried out by Ipsos B & A.
"While this progress is encouraging, the results clearly show there is still significant room for improvement in terms of age challenge and sale refusal to under-18s," the report said.
The office said it has required the operator of the National Lottery, Premier Lotteries Ireland (PLI), to "take tougher actions to drive an increase in awareness and compliance with the law by its retailers."
Regulator of the National Lottery, Carol Boate, said the 2024 mystery shop exercise is "part of the process we have undertaken to identify where risks exist so we can tackle them."
She said the results "clearly show that while great progress has been made since the 2018 mystery shop, there is still room for improvement in terms of age challenge and sale refusal to under 18s."
"While it is welcome that more retailers have "18+" signage in store and more staff are challenging test purchasers than in 2018 it is concerning that nearly three in 10 shops visited were still prepared to sell products to minors," she said.
Ms Boate said the regulator will work with PLI and retailers to "build on the progress made to date and adopt a zero-tolerance attitude towards the sale of age-restricted products to children."
National Lottery sales up 3.2% last year
The 2024 annual report also shows that National Lottery sales increased by 3.2% last year, compared to 2023.
Sales of National Lottery tickets reached €855.7m, up from €829.4m the previous year.
Online sales represented 18.1% of the total at €155.1m, which is up from 15.9% of total sales a year earlier.
Draw based games accounted for €540.1m of the sales, while there were sales of €315.6m generated through instant games, including scratch cards and interactive instant win games.
However, the figure transferred to the Exchequer for Good Causes during 2024, was down slightly year-on-year from €241m in 2023, to €238.3m in 2024.
€487.6m was won in prizes last year.
The annual report also includes sets out one licence breach by Premier Lotteries Ireland, the details of which were revealed last year.
The breach related to a technical issue with the "Check My Numbers" function between September and October 2022.
The regulator said the incident may have contributed to up to 394 prizes, worth at most €2,299, going unclaimed.
One of the prizes was worth €250, with the others ranging from €2 to €24.
The issue occurred after a third-party software update led to a number of players accessing the "Check My Numbers" facility on the lottery website when it should not have been available, as the draw results were still being verified.
Some of the players received a message saying their ticket was not a winner when in fact the numbers were winning numbers from that draw.
The issue was self-identified and reported by the operator to the regulator, which said PLI did not profit from the error and the issue was permanently fixed.
IT experts from Grant Thornton were commissioned by the watchdog to conduct an independent assessment of the PLI's full suite of prize-checking systems, both in-store and in-app.
No concerns were identified following this review
The incident was limited to the website, with the National Lottery app version of "Check My Numbers", the app's ticket scanner, and the in-store ticket validation machines all working as normal.
The operator discontinued the "Check My Numbers" facility at the end of last year, when it launched a new website and smart phone apps.
The breach resulted in the withholding of €23,000 from payments due to the operator, which was sent to the Exchequer to fund good causes.
The regulator said the €2,299 in unclaimed prize money was returned for use as prizes in other National Lottery games.
