The Free Church of Scotland is calling for a conscience clause to be added to the gay marriage bill.

In a response to the Scottish Parliament Equal Opportunity Committee's call for evidence, the Church said current legislation did not offer sufficient protection for people with a traditional understanding of marriage as a union between one man and one woman.

The Free Church wants a conscience clause similar to that in abortion legislation to be introduced to the gay marriage bill in Scotland.

A Free Church spokesman said it wanted reassurance from the Scottish Government that people with a traditional view on marriage would not be subject to prosecution but would be free to express their opinions.

"Given the lack of clarity from the Scottish Government on how this legislation will affect individuals who believe marriage is only between a man and a woman, we suggest the legislation is amended and adopts a conscientious objection clause similar to that of the 1967 Abortion Act with regards to the celebration of same-sex marriages," he said.

"This would provide indisputable guidance which would be hugely helpful, rather than having to establish precedents through the courts.

"The legislation has worked well for abortion, another deeply contentious moral issue, and it would make sense to have similar provision for same-sex marriage."

The call follows reports that millionaire gay couple Barrie Drewitt-Barlow, 42, and his partner, Tony, 49, are considering suing the Church of England so that they can get married in a church.

The Free Church spokesman suggested it was a matter of time before a similar case is brought to the courts in Scotland.

"Given what has already happened in England – where a court case is being brought against the Church of England with the ink barely dry on the Royal Assent – there is no doubt that we will see similar instances north of the border," he said.

"The issue is simply not going away, and we urge the Scottish Government to think again about embarking on this major social experiment before it further unravels the fabric of society."

The Free Church is also demanding safeguards in other areas. It wants the Equality Act to be amended to offer workplace protection for people opposed to same sex marriage on the grounds of religious conviction, arguing that it is inconsistent that choirmasters and organists should be protected against discrimination, and not registrars, teachers and other public sector workers.

It was also "unacceptable", the Free Church said, that parents did not have the option of withdrawing their children from all classes where gay marriage will be taught.