UPDATE: Telecom says services were restored to customers at midday. The outage lasted for four and a half hours. The company has been unable to gauge how many customers were affected, nor discover the cause of the problem.

Telecom Broadband (formerly Xtra) is experiencing multiple problems with its email systems this morning.

Customers on Telecom's Officemail service, which supports personalised domain names, are unable to send email full stop, while some customers with Xtra addresses cannot send email from a client such as Outlook.

Personalised domain names, which allow a person to send email from a customised address, are typically used by business customers.

Telecom, which did not immediately return calls, has posted the following service advisory on its website:

Some customers may be experiencing problems with email.
The issues we are currently experiencing are:

- Officemail customers will not be able to use webmail or send or receive emails through their email client.

- Customers with an @xtra.co.nz email address may not be able to send email, but can still use webmail and receive email.

The statement says the company is working to fix the problems, but gives no projected time for email to be back up and running.

The email outage is the latest in a series of service failures for the telco, which suffered a nationwide broadband outage after a failure in an Auckland exchange before Christmas, and a second failure last week that affected 10,000 customers following problems with a network system based in Wellington.