More than 13,406 complaints were made to the Telecommunications Industry Ombudsman about NBN services in the last financial year, which accounted for 11.9 per cent of all complaints received by the TIO, an increase from 5.4 per cent the year before.

Consumer advocacy groups believe a lot of the disappointment around the NBN could be mitigated with more transparency.

Teresa Corbin, CEO of the Australian Communications Consumer Action Network (ACCAN) said clearer information was needed to differentiate between theoretical speeds and what could actually be achieved.

"An ACCAN survey conducted in 2016 found that nearly 70 per cent of respondents had unsatisfactory experiences with their broadband services," she said.

"The top reason given was slow speeds at some times of the day.

"We believe that this shows that consumers need clearer information about broadband speeds.

"Currently, they rely on advertised speeds from retail service providers. These are often advertised using terms like 'speeds up to' which are confusing and do not reflect the actual speeds a consumer can expect from the service."

Telstra has begun contacting customers offering refunds and to downgrade plans where the advertised speeds are not being met, with retail group executive Kevin Russell admitting in a blog post that the speeds surrounding the network were "all a bit of a mystery".

The telco giant has called for the NBN Co to work with it and others in the industry to give customers a clearer idea of what speeds are achievable at their address, a move Optus supports.

"Optus supports the principle of a speed monitoring program that would help ensure consumers understand the speeds likely to be experienced over the NBN," a spokesman said.

"We believe it's important for the industry to work together to ensure that a consistent and robust process is put in place, and that the data disclosed is meaningful and relevant for customers."

A spokesman for NBN Co said it supported "any initiative that promotes transparency on retail speeds" available on its network and was working in collaboration with retail service providers "to help educate consumers and business owners".

"NBN believes the whole industry needs to play a role in educating consumers and businesses about the role speed plays and the factors that could impact the service ultimately received," he said.

Anything from the type of connection running the network to the property, to the distance between a premises and the node, to the modem or population can influence how fast the network performs.

Labor has continued to prosecute the government over the decision to run it largely as a Fibre-To-The-Node network, which uses the existing copper lines as its cornerstone,

"The NBN under Malcolm Turnbull is bad for consumers and bad for competitiveness", Opposition communications spokeswoman Michelle Rowland said.

"Under Malcolm Turnbull's second-rate copper NBN, consumers are worse off", Ms Rowland said.

Communications minister Mitch Fifield announced in April the Australian Competition and Consumer Commission would monitor NBN performance to allow customers to better compare speeds.