Telecom is defending a move to cancel the passwords of about 60,000 Yahoo! Xtra customers which left some customers without access to their email accounts.
The telco cancelled the passwords on Saturday night of the accounts they believe were compromised after a cyber attack.
It took the step as a safeguard to protect email customers and prevent information in emails being accessed following last week's incident which saw users' accounts hijacked.
Customers were forced to reset their passwords but some were left unable to access their accounts.
Telecom retail chief executive Chris Quin told Radio New Zealand the cancelling of the passwords was done to protect customers.
"We have a crisis situation on our hands because of this cyber attack.
"We know we're doing the best thing for customers by cancelling passwords and protecting their accounts and we ask for tolerance as we work through this."
Helplines were swamped with calls and customers were forced to wait around an hour to have their calls answered, despite the telco bringing in more staff.
"We've had an incredible load of calls off the back of an issue like this. We don't have resources to handle it when 60,000 customers need their password reset."
Mr Quin says around 90 percent of customers affected had been able to reset their password online, and said hard questions will be asked of email provider Yahoo as part of an investigation into the issue.
"This experience isn't satisfactory, that's why we're going to do a formal review of our email service," he said.
Telecom joined forces with Yahoo in 2007, partly to solve ongoing email issues with their Xtra service, but that hasn't worked, says technology commentator Paul Spain.
"I think it's worth realising that if hackers have had access to these accounts for some time, they've probably already got hold of people's contacts lists… this issue could go on for a long, long, long time, 'cause once the horse has bolted there's very little you can do about it," he told Firstline this morning.
"It's worth consumer realising using an internet provider's email account is probably not the best way to go – much better to have a Hotmail or Gmail-type address.
"It ties them back to their internet provider – they don't have choice of being able to change."
He suggests where possible, individuals – and especially businesses – should try and get their own domain name.
"For instance, I might have firstname.lastname@example.org, so that way I have complete ownership and you don't have issues of being tied back to an internet provider, or to Google, Microsoft, etcetera."
NZN/ 3 News