The Department of Communications, Information Technology and the Arts said in a request for tender it was planning to replace its "aged" PABX installation with a "modern, feature-rich IP telephony system".
DCITA said it was seeking supply of 950 IP handsets, call manager, associated software and networking equipment for four locations throughout Canberra.
Although requiring handsets, the tender said any solution that offered a soft-phone option would be viewed favourably.
The system would be installed and supported by DCITA's current voice and IT suppliers, according to the tender.
The solution must be delivered by 16 June, according to the tender.