Senator Conroy's shadow, Bruce Billson, said the architecture of the NBN is critical for enterprises and competitive telcos that may have invested to provide FttP and may seek to combine this with copper-based services.

"In addition, telcos which have installed D-SLAMS to offer ADSL and VDSL broadband services or have invested in their own fibre backhaul must be terrified about the prospects of their investment and businesses being left 'dangling' if a future Fibre-to-the-Node (FTTN) build bypasses the current exchanges.

"If these exchanges are bypassed by an extended fibre build that uses a node or street-side cabinet replacement for pillars as the point of interconnection with the broader network, many current arrangements will need to be re-engineered, renegotiated or written-off if the NBN architecture is not accommodating of these pro-competitive investments.

"Broadband users with these kinds of interests need to be heard and we have to provide a platform for their voices via the Senate Inquiry," he said.

Billson also signaled grave concerns for regional, rural and remote Australians, especially businesses in those areas, who could have had metro-comparable broadband rolled out by the middle of next year before the Rudd Government cancelled the OPEL network.

"12Mbps may not be enough for some businesses and specific applications but a proper role for government investment and intervention is to first address the under-serviced community needs and that was what OPEL was about.

"With the reported huge cost and timeframe over-runs Senator Conroy is overseeing with his shambolic NBN approach, it is not surprising that wireless providers are ramping up their technologies with speeds and offers to soak up demand for higher speed broadband in rural and regional communities," he said.