"They might be right 20 per cent of the time, but 80 per cent of the time they are completely wrong.
"I'm standing up for families around the motu."
The department had changed its name twice, he said, in an attempt to "change its history," but it could not do that.
"I'm sick of them tearing families apart," he added.
"They are part of the problem. They sign kids (into care) and they get molested."
He was aware of similar protests in Hamilton, Wellington and Christchurch, which gave him encouragement.
"We are starting to influence people across the motu," he said.
"We have had enough. We are sick of our people being hurt. I'm finished with these muppets. They tell lies about so many people for no reason. They tell lies about people who wouldn't hurt a mouse.
"Their credibility has gone. I don't believe a single word they say.
"I won't shut up, and I won't go away."
Oranga Tamariki says on its website that, where possible, it tries to keep families together.
"Taking children into care is a last resort," it says, while the department was increasingly working with iwi and communities to support at-risk children so they can stay with their parents.
An average of 240 reports of concern about children were received every day, 100 assessments aimed at helping families keep children were carried out every day, and of the hundreds of daily calls and assessments, four children would need the department's care.