He revealed on TVNZ's Q+A programme today that police had no specific targets when they carried out the raids.
"I think it's fair to say that there was no particular target or set of targets identified.
"But it was against a backdrop of a firearm, for instance, being dismantled and being sent down to Wellington, against a backdrop of discussions about a sniper rifle and a silencer, discussions about destroying property and explosives, and of course the threats in relation to people - to actually kill people."
Mr Marshall said while police did not have an identified target, there was growing alarm over actions over a number of weeks.
"It's a matter of balance - do we actually wait until something happens, the unthinkable happens, and then of course you can imagine the commentary then. Or do we, at an appropriate time, take action because we need to take action," he said.
"We don't know the specifics, but what we were convinced about, it wasn't just idle talk."
He was not aware of any current risk but would not comment on continued monitoring of the people involved in the raids.
"Suffice to say that we have no particular information about the Ureweras. We believe that group was disbanded, they've been exposed for what they are. I think the police actions have been very clearly vindicated by the High Court's judge."
Mr Marshall reiterated he would make "absolutely no apology" for the investigation, arrests and prosecution.
He would go to Ruatoki to apologise to innocent people who were "inconvenienced, distressed or indeed fearful".
"But I'm certainly not in the business of making a wholesale apology because we have nothing to apologise for."
Asked why John Key was allowed to visit the area two months before the raids, Mr Marshall said there was no suggestion he was a target.
"He wasn't the prime minister of the day and it was a very considered approach in terms of whether he should go there. He was invited there by senior iwi.
"We did a risk assessment in relation to that particular location. At that time, there was no threat assessment against him."
Mr Marshall said Mr Key had appropriate security.