Telecommunications Forum chief executive Geoff Thorn told Morning Report: "It's really unfortunate because the industry has put a huge amount of effort into supporting New Zealand through Covid-19 and now what we've got is critical infrastructure being damaged and what that's doing is potentially putting lives at risk if people in those areas can't get through to 111.
"It is affecting the connectivity ... the industry has done a lot to keep communication going in those areas but at the same time there is the potential for people making calls to emergency services not being able to get through."
He said towers had some security but it was not enough in some cases.
"That's something that the industry is now looking at. It's very hard, these sites are fairly remote. What they are doing, I believe they've got some cameras on some of them, but you'd have to talk to individual companies."
Thorn said the industry wanted people to report any suspicious behaviour around cell phone towers.
"These cell sites are needed to provide communications for people working from home, keeping in touch with family and friends, and so it's local communities that are affected, so we're asking local communities ... to contact police immediately."
Thorn said the chief science adviser's website had details about 5G and urged people to seek that "credible information".
"There's no evidence that we've seen that 5G is bad for humans. The best information that people can get is on the chief science adviser's website."