The Human Rights Commission and members of the Secular Education Network have applied to join court action against religion in schools.
The case was brought by Jeff McClintock against Red Beach School, north of Auckland.
Mr McClintock has been locked in a dispute with the school over its Values in Action lessons, where Bible stories are taught for 30 minutes a week.
He is a member of the network and laid a complaint with the commission about the lessons and the treatment of his daughter, who the Herald reported in 2012 was put in a corner alone when she opted out of the classes.
Applications from the commission and network campaigners David Hines and Tanya Jacob will be heard in the High Court at Auckland next month.
The Churches Education Commission, which runs Bible in Schools classes in more than 600 state primary schools, can call limited evidence.
In a statement, the network members say they want the case extended to include secondary schools, evangelistic youth workers and religious songs and prayers in school assemblies. They also want to call evidence from members of non-Christian religions.