Senior members of a national lobby for underground cabling claim to have received threats from angry residents that they will tear down any NBN cables hung overhead in their streets.
The group, Cables Underground, said it "does not advocate violence" and had attempted to counsel irate callers.
But it warned "these are only the ones with whom we come in contact" and said there were likely others that would escape its counseling and potentially vandalise an aerial rollout.
"It is highly predictable there will be a substantial electoral backlash," the assistant secretary of Cables Downunder, Greg Bleazard, said in a submission [PDF] to the Senate Select Committee for the NBN.
"One [caller] threatened to attach a beam and hook to a heavy truck and to drive it down the street tearing down any cables he comes across.
"Others have threatened to throw a hook over the cable and to then pull it down with the aid of a four wheel drive."
Earlier today, iTnews reported on a community group in Sydney's inner west that warned the Government against a repeat of Optus' hybrid fibre coaxial cable rollout in 1995.
The Haberfield Association successfully prevented Optus from stringing up aerial HFC cables in the suburb.
Cables Downunder said it coordinated the actions of independent community groups in the Sydney metropolitan area during the Optus rollout, but had since expanded its scope to become a national lobbyist.
Much of its work was cooperative and "behind the scenes" with local government authorities, Bleazard said.