The under-18s still find it easy to buy alcohol in supermarkets, cafes and sports club canteens, despite the ban which was brought in in 2014, according to research carried out on behalf of the health ministry.

Although there was a ‘slight improvement’ on earlier years, over 60% of 17-year-olds are still able to buy alcohol, the research, based on mystery guests, found.

The legal drinking age was raised from 16 to 18 in 2014 and the research has been carried out every two years since then. In total, a group of 17-year-olds made 2,300 attempts to buy alcohol.

Supermarkets and specialist stores are most likely to turn down under-age drinkers – some 70% passed the test. Night shops only rejected 35% of attempts to buy alcohol by the under-18s, and in cafes and bars, 80% of attempts were successful.

The worst performers were online shops – 17-year-olds were refused less than 10% of the time.

On average, efforts by 17-year-olds to buy alcohol were rejected nearly 38% of the time, compared with 36% two years ago. ‘I regard making no progress as a step backwards,’ junior health minister Paul Blokhuis said in a reaction to the results.

The minister will now focus efforts on getting shops and the hospitality industry to comply with the legislation. He is also working with local authorities in improving the supervision of the sector.