People who believe marriage is the union of one man and one woman must continue to be respected in Northern Ireland, The Christian Institute has said.
Yesterday, the law was officially changed with the first same-sex marriages set to take place next month.
Speaking on BBC Radio Ulster today, the Institute’s Simon Calvert said public order laws need to be fully updated to protect all those who disagree with the new law.
Mr Calvert welcomed changes that the Government had made – following a threat of legal action – but said it had to do more.
“We continue to have concerns about public order law generally in Northern Ireland – we think it needs reforming to protect free speech for everybody.”
“We’ll be watching very carefully”.
On religious groups, he said no-one wants to see faith leaders being sued for conscientiously objecting to officiating at same-sex weddings.
He also noted that in England and Wales, latest figures suggest only a fraction of the tens of thousands of places of worship registered to conduct weddings, carry out same-sex weddings.
“The mainstream position of Christian churches has always consistently been that marriage is the union of one man and one woman for life to the exclusion of all others.”
Referencing the Ashers Baking Company case, he said the courts had recognised that belief in opposite-sex marriage was worthy of respect.
And on education, he said schools must be careful to allow debate on the subject.
In November, The Christian Institute and pro-LGBT groups backed protections for charities, churches and public sector workers on same-sex marriage.
When it was introduced in other parts of the UK, protections were put in place on religious freedom.
The law on same-sex marriage was changed because of a vote by Westminster MPs in July.
At the same time, they endorsed the repeal of strong protections for women and unborn children.