Some NBN users are missing out on fast broadband internet, with new data showing their download speeds fail to reach even half of the maximum they signed up for.
The Australian Competition and Consumer Commission's latest report into NBN fixed-line speeds released on Tuesday shows mixed results, with most users experiencing fast internet speeds - even during peak hours.
The report states 70 per cent of tests had download speeds which were over 90 per cent of a customer's maximum plan speeds.
But seven per cent of NBN users are receiving less than half of the maximum speed of their plan.
The findings sparked calls from ACCC chair Rod Sims for internet service providers to help customers unable to get fast, reliable speeds.
"We also expect ISPs to inform customers of the speeds achievable on their network connections, and better match the plans they offer to those speeds," he said in a statement on Tuesday.
This quarter's ACCC NBN speeds report focused on the impact of underperforming services on overall speeds, finding they could improve by up to 9.4 percentage points if underperforming services reached their maximum speeds.
The second such report covers six major service providers - Aussie Broadband, iiNet, MyRepublic, Optus, Telstra and TPG - and their NBN fixed-line services in May this year.
Aussie Broadband customers experienced the fastest average download speeds, while MyRepublic finished at the other end of the scale.
Labor's communications spokeswoman Michelle Rowland said the report provided a much-needed baseline measure to hold ISPs accountable for the average peak hour experiences of NBN consumers.
"Three in four Australians on Turnbull's copper NBN cannot achieve top speeds, and without these measures there is a higher risk they will be sold plans that cannot be delivered," she said.
Industry body the Communications Alliance said while the ACCC's report showed excellent results by providers, the watchdog had disappointed by using maximum download speeds as a benchmark rather than advertised speeds.
"Providers should not make claims around maximum plan speeds and instead should advertise based on information about "typical busy hour speeds," chief executive John Stanton said.
Four million homes and business are now connected to the NBN, with the latest NBN Co monthly progress report showing the demand for higher speeds has almost tripled, increasing from 16 to 44 per cent.
Opposition Leader Bill Shorten vowed last month that a Labor government would put in place penalties for NBN Co for under-performance, allowing for compensation.
