RNZ previously revealed immigration authorities had hired the controversial firm Cobwebs Technologies.
Documents suggest another unidentified agency began using Cobwebs in October 2019.
The police have previously confirmed they began using a new Internet search tool in November 2019 after the mosque attacks, but would not name it.
This was part of their efforts to plug a gap in having no dedicated internet team leading up to the March attacks.
The Greens asked Police Minister Chris Hipkins about what Cobwebs' products police use.
Hipkins said they used a range of products to "detect and prevent harm to the community" but would not name them.
"Some of these products scan and collect publicly available information on the internet.
"Police's compliance frameworks and auditing ensure the products are used proportionately, appropriately and safely.
"The disclosure of the name of the companies and their products would be likely to prejudice the maintenance of the law," Hipkins said in response to a written question.
