Telecom has confirmed hundreds of customers of its Yahoo! Xtra email service have been hit with spam emails.
Telecom has reviewed its partnership with the email provider after almost 90,000 customers had their accounts used to send out malicious spam as part of a cyber attack in February.
The company said a number of people have received suspicious emails in a new incident.
A spokesperson for the company said on Wednesday she did not know how many accounts had been affected but it is likely to be in the hundreds.
She said the problem was not on the same scale as in February.
The company is advising customers who believe they've received spam to delete it immediately and change their password.