Some smartwatches designed for children are the security holes that make them vulnerable to hackers, a watchdog has warned.
The Norwegian Consumer Council (NCC) tested watches from brands including Gator and GPS for Children.
He said that he has discovered that attackers could track, intercept or communicate with the wearers.
The producers involved insist the problems have already been solved or are in the process of resolution.
The UK retailer John Lewis has withdrawn one of the smartwatch named models on sale, in response.
The smartwatches tested essentially serve as the basis of smartphones, allowing parents to communicate with their children, as well as keep track of their location.
Some include an SOS function that allows the child to immediately call their parents.
They usually sell for around Â£100.
NCC has said that he was worried that the Gator and GPS Kids watches and transmitted and stored data without using encryption.
He said that meant strangers, and using hacking techniques, to monitor the children as they moved, or a child seems to be in quite a different position.
The rights of the consumer watchdog Which? he criticized the “poor” watches, and said to the parents “would be shocked” if they knew the risks.
Spokesman Alex Neill said: “the Safety and security should be the top priority. If that cannot be guaranteed, then the products must not be sold.”
John Lewis stock a version of the Gator watch, even if it is not clear if it suffers from the same security flaws as the watches tested.
The firm said that it was to withdraw the product from sale “as a precautionary measure” pending “further advice and assurances from the supplier”.
GPS for the Kids, she said it had resolved the problems of security for the new watches and existing customers to offer of an upgrade.
The UK distributor of Gator watch said that it had transferred the data to a new encrypted server and was developing a new, safer app for the customers.