Complaints against the troubled National Broadband Network have risen again with the latest Telecommunications Ombudsman’s Report, released on Wednesday, showing significant increases in complaints over the past year.

As the government prepares to sell the NBN, levels of dissatisfaction against what critics describe as the worst infrastructure project in Australian history are extremely high.

In overall terms, residential complaints rose to a record 146,957, an increase of 8141, or 5.9 per cent.

Business complaints rose 8.7 per cent to 20,433, an increase of 1644.

The worst-performing telco by a considerable margin was Optus, with an increase of 35 per cent in complaints.

The next closest was Telstra, on a comparatively modest 7.7 per cent increase.

Telecommunications Ombudsman Judi Jones told The New Daily that Optus was well aware of the problem and her office was in constant communication with it.

“They are working hard on their processes,” she said.

“Hopefully next year will see a reduction.”

In terms of location, Queensland for the second year in a row showed the greatest increase in the number of complaints – 13.2 per cent.

“We can see nothing in the data to explain that,” Ms Jones said.

The next worst performing state was Western Australia, with an increase of 10.7 per cent.

In terms of volume, New South Wales remains the worst state, with 52,989 complaints, an increase of 4.9 per cent.

About 12 per cent of residents complained that they receive no service at all, while a further 19.1 per cent complained of intermittent service, dropouts and slow speeds.

A whopping 33.8 per cent of residents complained of either no customer service action or delayed action.

Businesses were even more dissatisfied, with 35.9 per cent complaining of lack of action.

The devastating impacts on business of the botched NBN rollout are clear: 16.2 per cent complained of no service at all. A further 13.9 per cent complained of intermittent service, dropouts and slow speeds.

There were more than 12,200 compensation payouts last year for both residents and businesses.

The maximum payout is $50,000.

While most of the statistics trended up across the year, Ms Jones points to a modest decrease in the final quarter as a hopeful sign the tide is turning.

But internet activists see it differently.

Former Internet Australia executive director Laurie Patton told The New Daily any decrease in complaints was likely to be a result of heavy wholesale discounting by NBN, introduced in panic and under government pressure.

The discounts allowed retailers to increase the bandwidth they purchased and saw congestion levels fall.

“The dilemma is the discounts are about to end,” he said.

“It was only a temporary measure. Our internet service is not going to get any better overall until we adopt 21st century technologies.”

Mr Patton said he sympathised with Communications Minister Mitch Fifield, who he says has been let down by NBN Co.

“The people who advised the government back in 2013 are the ones to blame, as are the current NBN Co board members who refuse to concede that what they are now building is a dud.”