Former NBN boss Mike Quigley has slammed the Coalition’s copper-based network as a “colossal mistake” after a senior German executive gave a sponsored speech backing the technology.

Deutsche Telekom chief technology officer Bruno Jacobfeuerborn, in Sydney for a conference partly funded by NBN Co, said his company initially thought the Australian Labor Party’s plan to rollout full fibre-to-the-premises (FTTP) was a “great idea” but soon switched to a Coalition-style multi-technology mix because full FTTP was “very ambitious” and inefficient.

Mr Quigley, NBN Co’s first CEO from 2009 to 2013, retorted by saying Germany’s copper-based network was very different to Australia’s.

“The world’s going fibre,” he told The New Daily.

“I can understand why Germany’s using a multi-technology mix approach because it’s an incumbent telco.

“If an incumbent telco is overseeing a national rollout and has existing infrastructure that’s in reasonable condition, then that would make sense to maximise long-term profits.

“But the NBN is a very large public infrastructure project and it didn’t have access to Telstra’s copper network and didn’t know what condition it was in.”

Earlier on Monday, Deutsche Telekom’s Mr Jacobfeuerborn said his company was initially inspired by Labor’s plan, but soon changed its mind.

“We looked at Australia’s [original] NBN and thought, wow, great idea – 95 per cent fibre to the customer. However, it’s very ambitious and you miss the efficiency you can access with existing technologies,” Mr Jacobfeuerborn told ABC Radio on Monday.

“And, for that reason, we thought it best to have a variety of technologies to use. It’s not a case of one size fits all.

“From what I see and hear so far is that we have a little bit of a similar situation.”

He said in Europe there is also a popular opinion that everyone should have access to the superior FTTP technology.

“We have the same discussions in Germany. If FTTP is the best value you can get, just build it? But that’s not the name of the game because you have to be as efficient as possible.

“From my perspective we are having the wrong discussion.

“We shouldn’t talk about the technology, we should talk about what the customer gets in the customer experience.”

However, Mr Quigley blamed “a significant proportion” of Australia’s NBN speed complaints on inadequate technology.

“It’s becoming more obvious to end customers that an FTTP-based NBN is a much better network than copper-based mix of technologies, from all angles – speed, reliability, longevity, maintenance costs and upgrade costs.”

Mr Quigley also blamed the Coalition’s copper-based model for the extent of the budget blowout from $29.5 billion to upward of $56 billion, attributing this to underestimated FTTN and HFC costs.

The New Daily contacted NBN Co for comment on its selection of speakers at the global broadband futures conference but did not receive a response by deadline.

Other speakers included Chorus New Zealand’s head of networks Martin Sharrock, Cox Communications’ Jeff Finklestein and Liberty Global’s Gary Mitchinson.