Telecom says a number of its Yahoo! Xtra email customers have experienced a resurgence of spam emails.
In February, almost 90,000 Telecom customers had their Yahoo! Xtra email accounts used to send out malicious spam, prompting Telecom to review its partnership with Yahoo.
Telecom said customers again began reporting spam emails on Saturday morning. The messages are requesting the user to click on links that direct them to third party websites.
Telecom corporate communications manager Richard Llewellyn advised customers who have received anything they believe is spam, even from a known contact, to delete the message and reset their password.
Mr Llewellyn said the company does not know how many people have been affected. He was confident Yahoo! is on top of the problem and said Telecom has no worries at this stage.