More than one in 10 NBN services are “underperforming” and rarely reaching even close to their maximum speeds, a new competition watchdog report has found.

The ACCC’s sixth version of the Measuring Broadband Australia report reveals internet speeds have decreased slightly during the busy evening hours, but the services are performing relatively well overall.

But the report did find that 12.4 per cent of consumers have “underperforming services” that are “rarely coming close to reaching their maximum plan speed”.

These are services that are achieving less than 75 per cent of their advertised speeds in almost all of the completed speed tests, and amounts to more than one in 10 NBN consumers.

The most impacted consumers are those that have paid for NBN50 or NBN100 plans over fibre-to-the-node connections, the report found.

The poor speeds are so dire that they impact consumers’ ability to stream content, conduct telecommuting and take part in online gaming and cloud services, ACCC chair Rod Sims said.

“We now want to see more action from both NBN Co and retail service providers (RSPs) to help the more than one in 10 connections that simply do not perform to their plan speed,” Sims said.

“In many cases, these limited speeds are caused by in-home wiring issues that can be fixed with a visit from a technician.”

If these issues are resolved, RSPs download and upload speed results in the report would improve by two to 6.8 percentage points in the peak hours, and their average upload speeds by 1.5 to 10.7 percentage points.

The Measuring Broadband Australia report is prepared by UK company SamKnows and uses data from volunteer households on various NBN services.

The latest installment of the report contains data on fibre-to-the-curb connections for the first time, finding that the service is reaching speeds broadly in line with fibre-to-the-premise and HFC, and “significantly above” fibre-to-the-node.

It also found that the participating volunteers experienced on average an outage of more than 30 seconds every one to two days, while Optus customers experienced 2.6 per day.

The issues surrounding the Optus outages have since been addressed, and are now comparable to other providers, according to the report.

The report contains state-by-state information for internet speeds for the first time too, with Tasmania found to have the highest download speeds, while the Australian Capital Territory and Western Australia are lagging behind.

Labor member for Fremantle Josh Wilson slammed the federal government over the slow internet speeds in Western Australia.

“An effective NBN depends on an evenly distributed high-quality network,” Wilson said. “Unfortunately Australia has neither, and WA is on the wrong side of a sharp digital divide.

“This will put us at a permanent disadvantage, reducing productivity and access to essential services in areas like health and education.”

Three internet providers – Dodo, iPrimus and Exetel – were found to not be meeting their advertised speed claims during busy hours, and the ACCC is now in discussions with them on whether these advertisements should be “immediately revised in light of these results”.

The report measured the average download speeds during busy hours for NBN fixed line residential services, with 100/40 services reaching 85.3mbps and 50/20 services at 41.3mbps.

Sims encouraged other Australians to volunteer to take part in the study.

“This program would not be possible without the support of our volunteers Australia-wide who have agreed to host a whitebox on their home broadband connection,” Sims said.

“Consumers whose service provider is not currently included in our reports are particularly encouraged to sign up.

“Measuring Broadband Australia continues to make a vital contribution to fostering competition and improving consumer outcomes by bringing much-needed transparency to the broadband market.”