More than a quarter of the 84,914 complaints made to the Telecommunications Industry Ombudsman (TIO) were about services delivered over the NBN.
The national broadband network is still not meeting consumer expectations with complaints continuing to rise as more homes and businesses connect to the network, the industry ombudsman says.
More than a quarter of the 84,914 complaints by residential and business customers to the Telecommunications Industry Ombudsman were about services delivered over the NBN.
The majority of NBN complaints made in the six months to December 31 were in regards to service quality, with customers unsatisfied by provider responses, while other issues were around connection delays.
NBN Co says of the 22,827 complaints to the ombudsman about retail services delivered over the network, it received only 1052 complaints to resolve - a decline of 16 per cent compared to the same corresponding period.
Ombudsman Judi Jones said while the increase in NBN complaints is not surprising given the growing number of connections to the network, the rise is still concerning and indicates that the service is still not meeting expectations.
"It is really important that the retailer listens and puts themselves in the consumer's shoes and looks at it from the consumer's perspective, figures out what to do and then does what they say they are going to do," Ms Jones told AAP.
She said recent changes to regulation and rules put in place to resolve complaints, including the consumer watchdog's enforceable undertakings, speed monitoring and NBN's move to temporarily slash the cost of top-tier internet speeds, are positive steps that will help improve the consumer experience.
While these changes aren't reflected in this six-month update, they could show a reduction in complaint numbers in the coming months, Ms Jones said.
"There are a lot of levers being pulled now so it is probably going to be hard to say which particular lever reduced those complaints," she said.
"But there is a lot of work being done to improve the consumer experience which is great."
Overall complaints rose 28.7 per cent on the same period in 2016, with multiple services contributing the bulk (30.8%), followed by mobile services (29.4%) and internet services (28%).
Complaints increased across all states and territories with Queensland, Tasmania, Victoria and Western Australia recording particularly high increases of over 30 per cent compared to the same period in 2016.
Ms Jones said most of those complaints were about charges and fees and provider responses and services but weather conditions in these regions also contributed to the climb.
TOP COMPLAINTS FOR TELCO CUSTOMERS:
1. Charges and fees
2. Provider response
3. Poor service quality
4. Connection/changing provider
5. No service
(Source: Telecommunications Industry Ombudsman's July- December 2017 Report)