The competition regulator has set a cap on the prices retail internet service providers such as Telstra, TPG Telecom and Vocus Group can charge wholesale customers to use their superfast broadband networks.
Australian Competition and Consumer Commission chairman Rod Sims said the main reason for setting a cap was to make sure retail service providers and consumers would not be any worse off on non-NBN superfast broadband.
"The draft prices have been set in line with NBN prices and will change with NBN prices over time. Prices will reflect growth in traffic across the superfast broadband sector, which will continue to drive down the average cost of wholesale aggregation services."
"We expect that these wholesale price changes will likely lead to lower prices for retail customers of superfast broadband providers," Mr Sims said.
The draft access determinations, released on Monday, will stop providers with NBN competing networks from charging more than the government-owned wholesale internet provider.
Superfast broadband services are defined as being able to provide 25 megabits per second download and 5 megabit per second upload.
Under Australian competition law, a provider with its own superfast broadband network must make it available on a wholesale basis for other retail providers.
The ACCC has set a cap on the aggregation charge to $15.25 per megabit per second each month, equivalent to the NBN's CVC connectivity virtual circuit charge. It has set the port per month charge at a similar level to NBN's access virtual circuit charge at $27 per month.
The cap on Telstra's fibre access broadband in South Brisbane has been set at a marginally different price because users are expected to move over to the NBN in the next few years, the ACCC said.
The price cap is unlikely to have a major impact of the likes of TPG, which launched its wholesale superfast service with a $4 CVC charge. Other major network providers are understood to be relatively unconcerned about the cap.
Networks supplying less than 12,000 end users are exempt from the cap. But the ACCC can step in if they start to charge too much.
"Most of these [networks] are monopolies, so you have to have some cap on a monopoly," Mr Sims said.
"The main facilities affected by this are those who go into new estates and hook them up," he said while noting it will still apply to providers who have superfast broadband services outside of new developments.
The government has decided that the NBN does not need to build over the top of existing residential services because they are being served to a certain standard.
"Most of these won't ever face competition from the NBN. If you've got a superfast system in there, and you're a new estate, why would the NBN bother to replicate that?" Mr Sims said.
Mr Sims said the price cap will evolve over time and stay in line with NBN wholesale pricing.
"If CVC pricing goes down, then these prices go down automatically," he said.
A Telstra spokesman said: "We are examining the details of the ACCC's draft decision and its impact on our South Brisbane and Velocity Estate networks. We look forward to continuing to engage with the ACCC through their process before a decision is finalised."