In the week of the final vote for Scotland’s equal marriage bill, gay rights campaigners have accused SNP MSP John Mason of attempting to wreck the bill by tabling a series of last-minute amendments.

A stage 3 debate and vote for the Marriage and Civil Partnerships Bill (Scotland) is set to take place on 4 Feb.

However, Scotland on Sunday reports that John Mason, the Scottish National Party MSP for Glasgow Shettleston, has tabled numerous amendments recently which purport to protect the rights of those who disagree with the legislation.

One of the amendments states that no public sector employee should suffer an “detriment” for believing marriage to be between a man and a woman.

This follows a similar attempt at a wrecking amendment made in August last year, where Mr Mason tabled a motion which said no one should be “forced to be involved in” same-sex marriages.

The Equality Network charity has cautioned that these proposed changes could threaten the legislation’s passage into law.

In a briefing paper, it also points out that the UK parliament has already rejected such amendments in the past.

The paper reads: “In our view, this amendment is discriminatory, unworkable and would potentially wreck the bill by preventing the main part of it coming into effect.”

Last night, Mr Mason said: “This is not intended to be a wrecking amendment. All my amendments are intended to strengthen the protections for those who disagree with same-sex marriage.”

In October last year, the SNP MSP said he believed civil registrars should be able to opt out of marrying gay couples in Scotland – in the same way doctors of faith can refuse to perform abortions.

The Scottish Parliament’s Equal Opportunities Committee unanimously voted to pass an amendment by MSP Linda Fabiani in favour of removing the spousal veto from the country’s equal marriage bill last month.

It means that, unlike in England and Wales, married transgender people in Scotland will no longer be forced to obtain written consent from their spouse before they can get legal recognition of their gender.

Stage two of proceedings for Scotland’s equal marriage bill was then completed. Positive amendments were passed and all the negative amendments, such as allowing opt-outs for registrars, were defeated.

The Marriage and Civil Partnerships (Scotland) Bill passed its first Stage One vote on 20 November.

A poll in December showed a majority of Scotland’s population support marriage rights for same-sex couples.

56% of Scots support the legislation going through Holyrood; 35% are opposed, while 8% are unsure.

The findings were welcomed by equal marriage campaigners who say MSPs should “take heart” from the level of support among the public.