The Irish Data Protection Commission says it’s received a breach notification from Fastway Couriers.
The customer data impacted includes names, addresses, email accounts and phone numbers, but the company says nobody’s financial data was at risk.
It’s understood that up to 450,000 people may be impacted.
In a statement Fastway’s CEO Danny Hughes says the issue is limited to delivery information only.
He says it’s distressing that the company’s IT system was compromised by a malicious hack as it’s exceptionally careful in every aspect of its data protection obligations.
He says he deeply regrets that people’s personal data has been compromised and is apologising to its clients and their customers.
Business Post Tech Correspondent Emmet Ryan says it’s a good time to update passwords if you’ve been doing a lot of online shopping.