He was disappointed the school was being tarred with that message.
Goodsir gave examples in the sermon of how the church had "infiltrated" the community by running a sausage sizzle at the Harbour Family Fun Day, organising Christmas in the Park or organising Oamaru's Easter egg hunt.
Independent school governance consultant Cleave Hay, who will conduct the review, wrote in the school's December 7 and 14 newsletters the Ministry of Education was not involved in the review.
He asked staff, parents and the community "to await the review and desist from using social media to address concerns or frustrations".
The issue has attracted a lot of attention on social media this week.
Hay met the board and parents in November last year and the school changed its "opt-out" policy for religious instruction.
Parents now made a "mandatory choice".
Goodsir said a small number of children now stayed home from school at the start of the morning once a week; and of those children at school "just over 50 per cent" were enrolled in religious instruction rather than the alternative "values" class.
Religious instruction had been held at the school since Oamaru South and Awamoa School amalgamated in 2001, he said, and he had been a board member at the school for two years, chairman for the past year.
Hay said interviews would be held at the school on February 13 and 14 next year and a report would then be presented to the board.
Principal Lloyd Bokser could not be reached for comment.
Ministry of Education head of sector enablement and support Katrina Casey said "a small group of parents" had included the ministry in its communications with the school principal and board.
When a state primary school was open for instruction, the teaching must be entirely secular, but schools were permitted to close for up to 60 minutes per week, and no more than 20 hours in the school year, for religious instruction or observance conducted by volunteers, she said.