The number of Christchurch residents spied on while trying to get their insurance claims settled after the quakes could be in the hundreds.

On Wednesday, Newshub revealed $180,000 of taxpayer money was paid to private investigators Thompson and Clark over three years to snoop on homeowners upset with Government-owned insurer Southern Response.

They include Cam Preston, who was deemed by Thompson and Clark to be a "threat" and potentially capable of murder.

But Newshub national correspondent Patrick Gower, who broke the story, told The AM Show on Thursday he could be just one of hundreds in Thompson and Clark's sights.

"Anyone who was on Facebook talking about their insurance claims and the way they were being dealt with by Southern Response may have been snooped on, on there. Anyone who went to a meeting or a protest about Southern Response... may have been spied on.

"There are potentially hundreds of people who are waking up today to find out they have been snooped on, spied and observed, followed potentially, or even infiltrated by undercover agents."