Telecom customers are facing new technical problems - this time with the voicemail on their home phone lines.

One Aucklander said he had lost valuable business because messages left on his phones were distorted into incomprehensible white noise.

The company seemingly has no idea how many people are affected: while its PR spokeswoman says they've had only about 100 complaints, an email to customers says 80 per cent of homes that use the call minder service were affected this week.

Steve Hart, a freelance writer who works from home in the North Shore, said the problem was beyond inconvenient.

"It first happened to me last Wednesday where one message was complete computer squelching, a terrible noise. It went on for the duration of the message."

Hart said two thirds of his messages since then had been affected by the fault and he was losing business as a result.

"I get calls from overseas for work, and that's a missed business opportunity when I can't tell who left the message or what they were wanting."

A email from Telecom customer care staff said the issue affected the vast majority of users with the message service.

"I would like to apologise for the problems you are currently experiencing with your call minder service," the email said.

"It is a known fault that has affected 80 per cent of customers using the call minder service."

But Telecom spokeswoman Emma-Kate Greer said on Friday that the number of complaints about the problem was much smaller.

"The information on that provided by email to the customer was inaccurate," she said. "We've had only about a hundred calls about this sort of problem."

Greer said Telecom had 2.9 million users of the service, which costs users up to $9.95 a month.

She apologised to Hart and other customers and said the problem was ongoing: "We apologise to the customers who have had a voicemail affected by static on the line and we are working to resolve this as soon as possible."

Telecommunications Users' Association chief executive Ernie Newman said the disruption to businesses like Hart's was "unacceptable".

The fault with call minder comes hard on the heels of yet another outage with Telecom's troubled XT network this week.

Thousands of users in Auckland and Northland experienced interruptions to coverage on Thursday that a Telecom spokeswoman said were "intermittent and solved within 2 hours".

Newman said although the call minder and XT problems were unrelated, Telecom's responses appeared similar.

"They seem to be back in the mode of denying they have outages. I understand they feel under siege, but if they have an outage they need to admit it and be proactive about fixing it," said Newman.

This outage marked the fifth time the XT network crashed. Multiple outages for users in Wellington and the South Island saw Telecom offer a multi-million dollar compensation package to customers.

Telecom's other woes

* 14 December, 2009: XT Network crashes south of Taupo.

* 27 January, 2010: XT Network crashes south of Rotorua.

* 16 February, 2010: XT Network crashes south of Taupo.

* 22 February, 2010: XT Network crashes south of Taupo.

* 26 February, 2010: 111 telephone network crashes in South Auckland.

* 8 April, 2010: XT Network crashes in Auckland.

Have you complained about the Telecom call minder fault? Email with the subject line 'Telecom'.