The trial, to start on July 4, will see Telstra staff around Australia test the 3G platform and functions such as voice and video calling.
The new network currently operates in six capital cities and works with the existing 2G equipment.
It is based on a network-sharing agreement Telstra inked with current 3G player Hutchison late last year.
Since then, Telstra's 3G service was running well on track, Telstra wireless and mobility managing director, Holly Kramer, said.
"We committed to being network ready by July 2005 and we have delivered an operating 3GSM network, integrated with our own customer support platforms in world's best practice time," she said.
"We will soon be in a position to offer customers a full suite of 3G services following the successful introduction of our Telstra Mobile Broadband service on 1xRTT EVDO technology, which was launched last year. It is currently available in selected metropolitan and major regional areas.