Telecom is seeking to win the confidence of customers with its "five nines" reliability campaign, but the reality for home phone and internet customers may be less impressive.

The country's biggest telco has blitzed newspapers, television screens and billboards nationwide with the "It Works" campaign as it tries to convince customers its network runs smoothly 99.999 per cent of the time.

Elaborate television advertisements, the work of ad company Saatchi & Saatchi, claim that Telecom's network reliability ranks with that of precision watchmaker Rolex and the US Geological Survey Agency's accuracy in map-making.


"Should our network get damaged it will usually heal itself. Should it get severely damaged it will automatically divert to a backup cable. Should that fail, technicians will divert traffic to other backup cables," the slick adverts explain.

But getting nothing but static when you pick up the phone or being suddenly disconnected from the internet may not be covered.

Telecom marketing general manager Kevin Kenrick said the reliability claim related to Telecom's "core" network.

That includes Telecom's public switched telephone network, its core data platform and international "points of presence".

From the exchange to the business or home front-door, where clumsy contractors can snag cables, Telecom's promise is not so bold.

"It's out of our control whether someone cuts the lines, and we can't influence what happens inside people's households and office buildings in terms of wiring and the devices they use," he said.

"We can't guarantee it across every access point because they are so variable."

Mr Kenrick added that the current campaign - part of a larger Telecom rebrand that could stretch over three years - was largely aimed at business customers.


A previous campaign on a similar scale encouraged consumers to "keep in touch with Telecom" and was aimed at the residential market.

"This is a message specifically communicated to the business market, because it's more relevant to them.

"If you're a retailer and your Eftpos doesn't work then you can't actually collect any money."

The Consumers' Institute chief executive, David Russell, said there was a danger that the general public would take the advertisements at face value, expecting the pledge to include home phone and internet use.

"They would be providing their customers with some solid ammunition to make a claim if they fell outside that 0.001 per cent when there are network problems," he said.

"But the only test of whether it's misleading or inaccurate is through the courts under the Fair Trading Act."

Telecom needs a strong brand name as it faces stronger competition from a merged Clear-TelstraSaturn in the business market and from Vodafone in the cellphone market.