Auction website Trade Me says it is unlikely minors will be able to buy wine through its site.
Wine sales have been allowed by Trade Me since last week, and conditions include sellers having an off-licence certificate.
The company says it has been given permission to operate wine sales by the Liquor Licensing Authority.
It says wine buyers must be over 18 and own a credit card, and need to purchase either six bottles or a full case of a particular wine.
Alcohol watchdog groups say they are largely unconcerned about the venture, but query how the age restriction will be monitored.
The Law Commission says it will discuss that matter with Trade Me management at the next week.