It has been revealed the National Broadband Network will be delivered via the existing copper network in most of Tasmania.

During the federal election, the Coalition pledged to honour its existing NBN contracts in the state.

After a review of the rollout, Tasmanians are being told most will not receive the NBN via direct fibre after all.

The executive chairman of NBN Co insists the contracts never guaranteed fibre connections to premises.

Ziggy Zwitkowski says the contracts to connect 200,000 homes do not specify the sort of technology which must be used.

He says the rollout in Tasmania will now be a multi-technology structure.

"Obviously in the previous model, the infrastructure was going to be an all-fibre infrastructure," he said.

"Post the election and post the strategic review, we've now agreed on a multi-technology model where we'll seek to use a existing copper network where we can.

"So this year it remains all fibre, at the end of this year it will be a mixture."

The Tasmanian rollout is being handled by Visionstream.

Mr Zwitkowski says the Visionstream contract does not specify a technology, only a volume of connections and performance conditions.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 20 minutes 22 seconds 20 m Ziggy Switkowski explains the changes to the NBN rollout. Download 9.3 MB

He says NBN Co has been working with the company to build momentum after the rollout stalled last year.

It is also discussing which technology makes the most sense for Tasmanians to give them access to high-speed broadband at an affordable cost to NBN Co.

"In most cases that means if there is existing high-performance copper in place, the addition of an overlay of new electronics means that you will move very sharply up the speed curve and we would look to Visionstream to make those connections," he said.

Copper connections 'not inferior'

Find out if your area is currently a fibre-to-the-premises rollout site here.

People living in the same suburb or town may now be connected via different technologies.

Mr Zwitkowski says some people will be disappointed with copper speeds of 50 megabit per seconds, but he expects technology advances to be able to double that in the next five years.

"The reality is that using the existing copper network, in this case, will give most people a speed experience vastly in excess they can actually use."

"And, under the current plan that's being developed most Tasmanians will get access to higher speed earlier than would otherwise have been the case."

He says it is debatable whether copper is inferior to fibre.

"I think that in almost all cases, except in the most demanding commercial users, an upgraded copper network will provide you with the speed and the quality of service which will more than meet the needs of 99 plus pc of Tasmanian and Australian users," he said.

"You'd be naive to believe that you can anticipate how this technology whether it's the technology of the infrastructure of the applications that you can foresee what they're going to be 10 years out.

"We can have an intellectual argument about the benefits of fibre versus copper, but I think it is quite academic. I don't think it's a real world issue."

Premier appalled by delivery change

Tasmania's Premier Lara Giddings wants the full fibre-to-the-home model maintained.

She told ABC Local Radio she is angry with the announcement and the way it was delivered.

"It's just absolutely appalling that the Australian Government is doing this to us because this is about Tasmania's future," she said.

"It's about our economy, it's about jobs, it's about how we future-proof this state, it is about how we compete on the global levels."

Lara Giddings says the Federal Government has not had the courage to tell Tasmanians.

"This is a broken promise from the Federal Government in relation to the NBN."

"Tony Abbott promised Tasmanians the NBN would be rolled out in full, under the contracts that had been prepared here in Tasmania and now he doesn't even have the guts or the courage for him or Malcolm Turnbull to provide that bad news."

The Federal Communications Minister, Malcolm Turnbull, has been contacted for comment.