Family First NZ says it will fight the Charities Board's formal decision to deregister the group.
The Independent Charities Registration Board announced on Monday the group's views on marriage and family cannot be determined to be for the public benefit, and it was stripped of its charitable status.
However Family First says its deregistration from the Charities Board is a breach of its freedom of speech, and it's appealing the decision - and not for the first time.
"We'll take it the whole way, because it's actually the principle of free speech that we're most concerned about. I mean, they seem to be targeting us because they disagree with our views on marriage and family which just happen to be held by huge amount of New Zealanders," national director Bob McCoskrie says.
"They seem to have us in their sights, and for some reason they're obsessed with getting us deregistered."
He warns the decision will have a chilling effect on other charities.
"We should always be concerned when the state determines what views are acceptable and what views are unacceptable. It's about freedom of speech," he says.
"If they speak on political issues, and if they talk about solutions to some of the social problems we see in New Zealand then that will be deemed political advocacy and therefore they're liable for deregistration."
Mr McCoskrie says it's not the first time he's fought the same decision, and says it's less-than-satisfactory trudging back to the same court.