Church leaders will use their Sunday sermons this month to implore their congregations to speak out against gay marriage.
With three weeks left for submissions on the bill to legalise gay marriage, the New Zealand Christian Network has asked members to write to the Government in opposition of the law change.
In an email to be "read out in churches" this month, the network encourages Christians to "take time to seek God's heart before writing their submission with grace and truth".
National director of the New Zealand Christian Network Glyn Carpenter said it was "highly probable that this bill will not be good for New Zealand".
"This bill on its own will not bring about the destruction of society as we know it," he said.