Telecom's new 3G mobile network will be open for business earlier than expected, with the company saying services on the XT Network would be available to customers from 6.30pm on May 13.

Previously Telecom had flagged a June date for kick-off of the new network, which will carry the company's hopes into the next stage of its mobile competition with Vodafone.

Telecom is investing more than $574 million in the new network over a two year period, with efforts to ramp up anticipation including television adverts featuring Richard Hammond of British TV show Top Gear.

Announcing the launch date today, Telecom chief executive Paul Reynolds said the new mobile network would be operational across the country from launch day.

Telecom also said today that a new handset from Sony Ericsson, the W995 with 8.1 mega pixel camera, Walkman music player and Outlook email support, would be available to Telecom customers before any others in the world from July.

From launch day a Samsung handset, the F480 which has a touch-screen would be available exclusively to Telecom, the company said.

Reynolds said the XT network would provide the best genuine coverage across New Zealand, offering superior network performance with faster mobile internet.

Along with the launch of the new mobile service, Telecom said it was rolling out a new design and fit-out for retail stores.

Six stores would be open with the new design by launch day with 12 further stores to be refitted over coming months.