Outdoor clothing and equipment retailer Kathmandu is investigating a suspected customer data breach on its trading websites.

Photo: RNZ / Alexander Robertson

The company said an unidentified third party gained unauthorised access to its website platform between 8 January and 12 February and might have captured personal information and payment details of customers.

"Kathmandu is notifying potentially affected customers directly," chief executive Xavier Simonet said.

"Kathmandu advises any customer who believes they may have been impacted to contact their banks or credit card providers and follow their recommended advice," chief executive Xavier Simonet said.

It did not give a number of how many it believed might have been affected.

"Kathmandu takes the privacy of customer data extremely seriously and we unreservedly apologise to any customers who may have been impacted."

Mr Simonet said Kathmandu was working with IT and cyber security consultants to investigate the extent of the breach but has confirmed that its online store was secure.

Mr Simonet said relevant privacy and legal authorities were being notified of the breach.