The Civil Aviation Safety Authority will replace its private branched exchange with unified communications in 11 national offices.
The air safety regulator said its offices in Canberra, Brisbane and Perth ran hybrid analogue and IP telephone systems.
And it wanted to give its other offices the same abilities.
It was seeking information from vendors on the costs and time to do the project.
Its current voice system was based on Aastra and Ericsson.
"It is envisaged that this implementation will involve the replacement of the existing PABX-based systems with a purely Internet Protocol voice communication system," the agency said in tender documents.
It needed to function with the agency's virtualised Exchange 2010 email system and corporate BlackBerry Enterprise server.
And it had to work with Windows 7: "CASA is moving towards the use of Windows 7 as the standard operating environment and intend to commence deployment to laptop users in the second half of 2010 with a desktop deployment in 2011".
The agency will roll out Microsoft Office 2010 by the first half of next year.
CASA said it wanted the system to integrate with its Tandberg videoconferencing kit and be used in its call centre.