NBN Co has revealed its interim satellite service will launch in July 2011 at half the peak speeds to be offered when the company launches its own satellites in 2015.
The interim service will be provided by Optus and IPstar.
NBN Co has signed a managed satellite services deal that includes some satellite capacity and is worth up to $200 million.
It will pay IPstar just over $100 million for additional capacity.
NBN Co will offer retail service providers a wholesale service with peak speeds up to 6 Mbps downlink and 1 Mbps uplink.
The company said last year that when it launched its own satellite service, it would provide speeds in tiers of 12/1, 12/2 and 12/4 Mbps.
An NBN Co spokesman said that the company "aimed to achieve speed and service improvements, using existing satellite capacity, by investing in ground station upgrades including new satellite technology together with the latest modern equipment".
NBN Co said it would also install and maintain all premises-based terminal equipment and dishes.
The interim service was still in a test phase with 400 existing customers from two retail service providers.
From July through to October, about 300 "priority one" residents and businesses – described as "those who currently have no alternate access to broadband services" – will get the interim service.
An Optus spokesman said that those initial services would "leverage Optus' existing premium broadband Very Small Aperture Terminal (VSAT) service platform".
"The service will use capacity on Optus' D-Series satellites," the spokesman said.
"Optus will be responsible for managing the project and will partner with Gilat Satellite Networks Australia to deploy VSAT network equipment at a number of satellite gateways and end user premises throughout Australia."
NBN Co said it aimed to be provisioning 1,000 new services a month from November.