LEIGH SALES, PRESENTER: The National Broadband Network is stretching further across Australia every day. As it does, the internet speeds we were promised are being put to the test.

Complaints about speed and reliability are so widespread that the corporate watchdog has taken the surprising step of asking volunteers to have their home internet monitored.

One place keen for answers is the Queensland city of Gympie. It hooked into the NBN 15 months ago but as 7.30's Peter McCutcheon found, many residents are less than happy.

PETER MCCUTCHEON, REPORTER: Hopes of a high speed future have come to a screeching halt.

SHARLENE MAKIN, CEO ROADCRAFT: I question the whole, their selling point of fast and reliable. It hasn't been our experience.

PETER MCCUTCHEON: How would you describe it?

SHARLENE MAKIN: Frustrating.

So Glenn, what is the internet speed we've got at the moment?

PETER MCCUTCHEON: The head of a Queensland driver education company says her business has been hampered by unreliable internet speeds and frequent dropouts.

GLENN: The little wheel is still spinning at the top. I just clicked retry.

SHARLENE MAKIN: It's all over the place. You never know what you're going to get. It's really hard to plan when you absolutely need internet, like to pay your 16 staff, it could just die.

BEN RICHES, PRESIDENT, GYMPIE CHAMBER OF COMMERCE: I haven't heard anyone that's just completely happy and when you're promised something, I would like to see it delivered.

PETER MCCUTCHEON: The promise of bringing fast internet speeds to Gympie was made early last year, one of the first regions to benefit from the Coalition's pledge of a faster rollout.

WARREN TRUSS: It's really exciting to be here in Gympie, and I note the sign, the NBN is in Gympie and it's here with the full range of technology.

PETER MCCUTCHEON: The most common form of technology was so-called fibre to the node, the Coalition's cheaper but slower option to Labor's original National Broadband Network, or NBN plan.

The high speed fibre is connected to street side nodes that connect to buildings using existing telephone copper lines.

TIM JENSEN, BLU LOGISTICS: This records all the milk we collect from farms and what we transport to factories.

PETER MCCUTCHEON: Last year, Tim Jenson told 7.30 this technology with the promise of a faster rollout was good enough for his milk trucking business.

TIM JENSEN (March 2016): I think what we're stuck with now, and what fibre to the node will give us is a vast, vast improvement, and probably one of those things we are probably, we're happy that it has come today, and not in something else, maybe it's potentially faster in another two or three years' time.

PETER MCCUTCHEON: A year later, Tim Jenson is still waiting for the show to get on the road.

TIM JENSEN: Still waiting for NBN and we've had advice that it will be September this year that it will be connected up, September this year.

PETER MCCUTCHEON: That must be frustrating?

TIM JENSEN: Yeah, it was quite, I suppose the expectation was there that we could get it now and it wasn't. So that was probably more the point, yeah.

PETER MCCUTCHEON: Telstra has apologised for the delay.

On the other side of town, internet speed is everything for video producer, Luke Soanes. He told 7.30 last year he hoped promises of speeds of up to 100 megabits per second could be delivered via the fibre to node technology.

LUKE SOANES, VIDEO PRODUCER (March, 2016): It's still yet to be proven. Until we actually really put it to its test and they turn us all on and we start testing, I won't really know exactly what I've been given.

PETER MCCUTCHEON: Fifteen months later, this scepticism is proving to be well founded. Even though his home office is almost directly opposite a fibre node.

When I spoke to you, you were looking of speeds of up to 100. What did you achieve in getting?

LUKE SOANES: At the moment it's varying between 40 and 50, download.

PETER MCCUTCHEON: What are you paying for?

LUKE SOANES: I'm paying for 100 down, 40 up.

PETER MCCUTCHEON: After being contacted by 7.30, Telstra sent a technician to change Luke Soanes' modem and he's now getting speeds of over 80 megabits per second.

BEN RICHES: I have had a lot of conversations with different business owners who have got NBN on and to be honest, I haven't heard anyone say, wow, it's great. I haven't really heard any stories where it's gone smoothly at all or anyone that's really receiving the speeds that they're promised and even if they are getting those speeds, it can be very inconsistent.

PETER MCCUTCHEON: To put the claim to the test, 7.30 asked NBN Co for an example of a satisfied customer in the Gympie region.

They referred us to the website business 'Stay at Home Mum'. This multimedia enterprise is connected to the network via wireless rather than fibre to the node technology because it's in a more remote area.

The business manager here says speeds in services have definitely improved since in NBN arrived.

BRENDAN ALLEN, 'STAY AT HOME MUM: It's been an improvement, it's been an improvement over what we had. But it's certainly not a massive difference from what we had in the past, no.

PETER MCCUTCHEON: NBN Co says overall, it has delivered on its promise to deliver fast internet speeds to service providers in Gympie.

KYLIE RITCHIE, NBN CO: But I really stress that it's a wholesale speed. So what people receive in their home may not be that speed, or is likely to not be that speed and that's based on a number of factors that are outside of our control.

PETER MCCUTCHEON: That's a grey area that infuriates Gympie's driver education school. As they try to pin down who is responsible for their internet dropouts and speeds of less than half of the up to 100 megabits per second they paid for.

Their service provider, Telstra, initially told 7.30 it could be a problem with the NBN copper network but has since said it has discovered a fault in the businesses own equipment.

SHARLENE MAKIN: Honestly, I don't know where the fault was. Everyone wants to blame somebody else.

PETER MCCUTCHEON: You don't know who to blame?

SHARLENE MAKIN: No, no. So my staff have tried hard, I know that.

PETER MCCUTCHEON: Advocate groups and even some telcos argue NBN Co could make it easier for consumers by publicising its own estimates of maximum obtainable speeds for each user along the fibre to node network, it's so-called secret data base.

But NBN Co is reluctant to go down that path.

Why doesn't NBN want to be in that space of giving customers more information?

KYLIE RITCHIE: It's a very difficult balancing act there because our customers are the retail service providers.

PETER MCCUTCHEON: The National Broadband Company says it already supplies that information about maximum speeds to service providers.

But a lot of people blame the NBN for slow internet speeds. Wouldn't it be of interest to share that information with customers?

KYLIE RITCHIE: Look, we are certainly working to share that information with customers but as I said, we think the RSPs or the retail service providers are absolutely the person or the company that is in the best place to be sharing that information with their customers.

PETER MCCUTCHEON: One of those service providers, Telstra, concedes a small number of customers in Gympie are not getting the speeds they paid for. And in some cases, they're been reimbursed.

This is one of the first areas in Australia to have fibre to the node and after 15 months, many customers are still trying to work out the lines of responsibility.

LUKE SOANES: I'd say it's a combination between Telstra and NBN. They're ironing out the system so they're still trying to figure it out.

SHARLENE MAKIN: We need total transparency so that as businesses we can plan.