However, they will not themselves be allowed to conduct gay weddings within the church.

Last year, the assembly agreed that ministers could enter into civil partnerships.

This decision means the Kirk adopts a position which maintains a traditional view of marriage between a man and woman, but allows individual congregations to "opt out" if they wish to appoint a minister or a deacon in a same-sex marriage or a civil partnership.

Any wider consideration of the theological understanding of same-sex marriage will not take place until the Theological Forum presents its report to the Kirk next year.

These latest changes will differentiate the church from the Church of England, which bans clergy from being married to partners of the same sex and has refused to allow gay church weddings.

First Minister Nicola Sturgeon attended the formal opening ceremony on the Mound in Edinburgh

Other topics to be discussed at the six-day assembly include the European Union referendum, corporal punishment of children, climate change and the refugee crisis.

Members will also discuss exploring ways of promoting the Church through the internet and social media, including a proposal to develop online congregations.

The assembly will also consider changing the date of the gathering to June to allow more young people to attend without disrupting their exams.

On Wednesday the Archbishop of Canterbury will become the first head of the Church of England to take part in a debate at the general assembly.

The Most Reverend Justin Welby will speak to a landmark report, which proposes that the two denominations enter into a historic ecumenical partnership.

The Archbishop of Canterbury will become the first head of the Church of England to take part in a debate at the general assembly. Pictured with Church of Scotland moderator Rt Rev Dr Angus Morrison

At the General Synod in London in February the Moderator of the General Assembly of the Church of Scotland, the Right Rev Dr Angus Morrison, took part in a debate on the Columba Declaration which formally approved the agreement.

Dr Morrison said: "We all look forward to welcoming the Archbishop of Canterbury to the General Assembly on Wednesday to speak to the historic Columba Declaration.

"It was my privilege to address the General Synod of the Church of England on the same document and by a very large majority the Synod affirmed it.

"I am confident that our General Assembly will do so too.

"In itself, the declaration is largely of a symbolic nature but it does pave the way for our further growth in fellowship and for extending partnership in mission as sister and national churches who share many common roots, challenges and opportunities."

Former Archbishop of Canterbury Dr Rowan Williams addressed the General Assembly in 2012 but did not take part in a debate.

First Minister Nicola Sturgeon attended the formal opening ceremony in the building on the Mound which used to be home to the Scottish Parliament until 2004.

More than 850 commissioners from across Scotland, the rest of the UK, Africa, Asia, North America, Europe, the Middle East and the Caribbean have registered to attend.

Dr Andrew Barr will become the new Moderator of the Church of Scotland

Dr Morrison is to stand down from his 12-month role as moderator and will be replaced by the Rev Dr Russell Barr, the founder of Edinburgh-based homelessness charity, Fresh Start.

Dr Barr has announced his intention to use his year in office to highlight the plight of homelessness in Scotland.

Speaking after he was elected, the 62-year old, who is minister at Cramond Kirk in Edinburgh, said he was "excited, honoured and overwhelmed".

The Assembly was first held in 1560, the year of the Scottish Reformation which marked the beginning of the Protestant Church of Scotland.

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