A Grey Lynn health shop and inner-city liquor store were caught breaking the rules in a recent police sting.

An inner-city Auckland liquor store manager says bad eyesight is to blame for selling booze to a minor.

Thirsty Liquor, on Victoria Street West, has been banned from selling booze for three weeks after three strikes for bad behaviour.

The store became a test case for party pills in 2012 after police twice warned the owner against selling the pills.

In the latest incident store manager Raghavender Reddy Muthani sold pre-mixed Vodka Cruisers to a 16-year-old girl in May.

Muthani checked the girl's identification but failed to see she was underage.

"It was a fault in my eyes," he said.

After the incident Muthani had his eyes tested and was given stronger prescription lenses.

A letter from his optometrist was presented when he appeared before the Alcohol Regulatory and Licensing Authority.

However, the authority ruled the company had "demonstrated a cavalier approach to the laws" around alcohol.

This was not the first time the liquor store has been in trouble with authorities.

Police asked all Auckland off-licenses to stop selling legal highs prior to a law banning party pills in 2013.

All agreed, apart from the owner of Thirsty Liquor, Suresh Patel, who continued to sell synthetic cannabis in 2012.

The company, owned by Liquor and Tobacco City Ltd, became a test case for legal highs and had its license suspended for 24 hours.

Muthani said the latest ruling would be hard for business.

Thirsty Liquor's license to sell alcohol was suspended for 21 days from November 23 until December 14.

Muthani also had his manager's certificate suspended for 28 days from December 28.

This meant the store could potentially go seven weeks without selling alcohol, during the busy festive season.

Thirsty Liquor must also make the store brighter to help staff read identifications.

Meanwhile, a Grey Lynn health food shop was also snapped for selling alcohol to a minor.

Huckleberry Farms, known as Harvest Wholefoods, had its license to sell alcohol suspended for five days, starting November 28.

The Alcohol Regulator and Licensing Authority also suspended the manager's certificate for 28 days.

Manager Somboon Khansuk said the shop assistant who sold the alcohol had been tired and thought the person looked older.

The store has since changed its procedures so alcohol purchases must be approved by a duty manger.

Organic alcohol was only a small proportion of its sales, he said.