Telecom has been forced to admit their Yahoo! Xtra email service has been hacked and will launch a review as hundreds of customers continue to receive spam mail.

The company says it is the victim of two separate but potentially related attacks that resulted in customers receiving numerous spam emails in the last three days.

Telecom has been hit by two separate phishing attacks.

Telecom reports it was first notified at 4pm on Saturday and later advised by Yahoo! early on Sunday morning the issue had been resolved.

However the company is still asking customers who have receive spam emails not to open them or the website link.

Telecom retail chief executive Chris Quin says the company will undertake the a review in the next two months and will include a comprehensive assessment of the Yahoo! Xtra service in consultation with service provider, Yahoo!

'We share the frustration that our customers have been experiencing over recent months. We fully appreciate that repeatedly saying ‘sorry' doesn't cut it anymore. We are committed to taking a close, hard look at the best way to meet our customers' email needs.”

Telecom head of external media Jo Jalfon says the first attack was a phishing attempt with some Yahoo! Xtra email customers receiving emails with a suspicious link from people on their contact list.

If the customer clicked on the link, then similar emails would be sent to certain contacts on their address list.

The second attack shows the security of some Yahoo! Xtra email customer accounts may have been compromised, making it possible for emails to be sent from these accounts without the customers' knowledge.

It is believed the emails are hijacked by spammers attempting to gain confidential information and credit card details from users.

Jo says it is difficult to give a definitive number of customers affected, but the company has received about 750 phone calls which has subdued since the attack was registered.

'This number is slowing down and there are more people ringing in to change their password as they have forgotten it.”

Chris says Telecom takes the online security of all its customers extremely seriously, but admits no system is 100 per cent bulletproof, as they have seen from the cyber-attacks by global criminals becoming increasingly sophisticated.

'For email services we rely on our partner Yahoo! which as a global email provider, has very advanced and sophisticated security systems. Yahoo!'s systems screen out the vast majority of malicious spam and email, which accounts for more than 90 per cent of total email traffic.

'We are currently working with Yahoo! to investigate further. We would like to apologise to all our customers for any distress or inconvenience caused and assure them that we are doing all we can, in conjunction with Yahoo!, to resolve this incident.”

All customers are advised to reset their email passwords and anyone who receives suspicious emails should delete them immediately without clicking any of the links contained in the email.

Spam characteristics include emails will be from a recognised email address known to you, it will either be a Yahoo! or Xtra email address and will contain only a link which you are advised not to open.

Users should contact the Broadband Helpdesk on 0800 255 598 about any problems.