Family First has led a number of public campaigns against legislation including the anti-smacking law and the same-sex marriage law.
The organisation says its traditional view of marriage is one of the key reasons for the deregistration and it will fight any attempts to deregister it.
When announcing in 2013 its intention to deregister Family First, Charities Services said Family First does not advance religion or education, nor promote a benefit to all New Zealanders.
Promoting debates on particular points of view was not a charitable purpose, it said.
Family First has maintained its tax-free charitable status while the appeal is ongoing.