He called it an insult to victims of crime by gang members.
"A Minister of the Crown going to their gang pad not only gives them credibility, but emboldens them in terms of what they're trying to do in our community. I find that absolutely shocking."
A day after Davidson's visit, Brown said he received three threats from what appeared to be a Mongrel Mob member - though from a different chapter.
"I've had a number of threats come through basically saying they're going to shoot me," the Pakuranga MP told reporters at the time.
Judge Michael Mika said this was a frightening and chilling experience for the victim.
Davidson told reporters her visit to the Mongrel Mob was about engagement with whānau-led solutions, "and that includes all whānau".
"It's vital we talk to a range of communities and I was happy to accept their invitation."
Waikato Mongrel Mob president Sonny Fatupaito said in a statement the death threats were wrong and should not be tolerated "by anyone, especially by people like us".
"I stand with him [Brown], as we all deserve to support and protect our families, no matter where we come from or the seemingly deep chasm separating us, which probably will continue."
Brown previously clashed with the Waikato Mongrel Mob at a parliamentary select committee in March.
"When are your members going to hand in their firearms and stop selling meth, which destroys lives in our community?" he asked the chapter's public relations liaison Louise Hutchinson.
He said there had been a lot of publicity about the reforms the kingdom's leader Sonny Fatu was trying to put in place, but "until you stop selling meth to the community across New Zealand and hand in your guns, I'm not going to believe it".
Hutchinson responded by telling Brown to come to the Waikato to see for himself, adding that Fatu didn't have any guns.
