HOUSEHOLDS and businesses should end up getting cheaper broadband deals under the NBN's revised pricing rules, the consumer watchdog says.

And Australian Competition and Consumer Commission chair Rod Sims said the draft regulations meant any cost blowout to the project - which had now hit $37 billion - would not flow on to internet bills.

However, it would be spread across taxpayers.

The ACCC has released a paper on the NBN's "special access undertaking", the terms by which the monopoly can recover costs over the next 30 years.

The NBN Co has committed to freezing wholesale prices for the first five years of the plan, and Mr Sims said there was enough retail competition to ensure affordable broadband deals.

He said the revised regulatory framework, proposed by NBN Co after fierce opposition to its first draft, was a better long-term outcome for customers.

"They will be paying less, the price will reduce over time," Mr Sims said.

The competition tsar said if the project's overall cost increased, this would not flow on to broadband prices offered by retailers.

"If they do spend too much, then consumers will be protected," Mr Sims said. "The less they (NBN Co) spend, the faster those prices will come down."

This would mean taxpayers bore the risk of any NBN cost blowouts, rather than the broadband consumers.

Some of the issues the ACCC will probe during its consultation with industry and consumers include a controversial "usage" charge, and whether there are enough incentives to ensure product quality is increased over time.

Originally published as Taxpayers to cop NBN blowouts