National Broadband Network chief executive Bill Morrow has warned there may never be a time when all Australians get the fastest available internet speeds, as such a project would cost “billions and billions” of dollars.

The cost of rolling out the required technology to enable Australians living in all regional areas to access 100Mbps speeds is so high, the NBN Co has "killed" any plan to provide it and has taken it off the road map, Mr Morrow said at Senate Estimates.

NBN Co boss Bill Morrow does not expect regional Australians on fixed wireless connections to ever get 100Mbps speeds. Credit:Dean Sewell

The NBN is obligated to provide all businesses and premises with access to at least 25Mbps peak data speeds, with the majority to have 50Mbps. So far, most connected households have opted for 25Mbps plans although the trend is improving for faster speed tiers.

In metropolitan areas and regional cities, households are typically able to buy up to 100Mbps speed plans when they move on to the NBN, while those on fixed wireless connections in rural and remote areas can usually get up to 50Mbps. Fixed wireless uses towers to transmit data over radio signals to an antenna installed onto a home, and is the chosen connection type when houses are kilometres apart from each other. How far a home is away from a transmission tower directly affects speed.