The Telecommunications Users Association says there is little Telecom can do about a resurgence of spam email attacks on Xtra email accounts.
Telecom reviewed its partnership with Yahoo Xtra after almost 90,000 customers came under a spam attack in February.
Viral emails, which feature a general web link to a third party website, began circulating on Xtra accounts again on Sunday.
Telecom is recommending its customers change their passwords to block unwanted emails.
TUANZ chief executive Paul Brislen said that's all Telecom can do, and most of the blame sits with customers who didn't act after the attack in February.
Mr Brislen said spam cannot be stopped and it's vital customers change their passwords frequently.