Three domestic terror attacks prevented by New Zealand's spy agencies have shown the complex scale of threats the country is facing.

GCSB boss Andrew Hampton has revealed how its capabilities were used in three counter-terrorism operations

They included a person making bomb threats last year and increasingly concerning behaviour online from a white extremist.

Disinformation Project Director Kate Hannah told Mike Hosking it's difficult to tell if someone behaving in an anti-social way online will become a genuine threat.

She says in the last two years they've seen an increase in people's preparedness to turn up and protest and this indicates if a person is more likely to take it to the next step.

LISTEN ABOVE