Edinburgh, UK - Allowing the playing of music and singing of hymns during worship is to be discussed at the Free Church of Scotland general assembly in Edinburgh.
Free Church congregations sing psalms unaccompanied by musical instruments.
The Reverend David Robertson said the move could attract new worshippers to congregations suffering from declining membership.
But the Reverend Iain D Campbell said the changes could damage the unity of the Church.
Mr Robertson, minister of St Peter's Free Church in Dundee and editor of The Recorder monthly magazine, said traditional psalms would not be sacrificed if music and hymns were introduced.
However, he said changes would attract new people to small congregations that chose to widen the way they worshipped.
Speaking to BBC Radio Scotland ahead of the assembly's debate, he said: "We will always be a psalm singing Church and I hope we will always have a cappella singing. I think it is a great tradition.
"But I also think it is Biblical, but not the only Biblical way to worship God.
"Right now we cannot afford to turn away people or to chase people away from our own Church."
Last July, Mr Robertson suggested traditionalists within the Church of Scotland could set up a new group with the Free Church.
He said those with the same "theology and faith" could come together.
The minister's comments followed the Church of Scotland's appointment of its first openly gay minister.
Mr Robertson said rather than Church of Scotland members splitting to form another denomination, they could join with the Free Church.
But he said changes would have to be made - including allowing music and hymns during worship.
In his interview with BBC Radio Scotland he said the word psalm meant singing with a stringed instrument and added that the Scottish tradition was rooted in the Reformation of the 16th Century.
It split the Church into Catholic and Protestant factions.
Mr Campbell, from Lewis on the Western Isles, urged caution on making changes.
He said: "If there has to be a change it has to be grounded on very clear scriptural principles which I hope will maintain the unity of the church.
"Nobody wants to see another division within the denomination."
Legal argument
The biggest split in the Church of Scotland and the forming of the Free Church of Scotland followed later in 1843.
More than 450 ministers walked out of the general assembly in a row over the process of appointing ministers.
The dispute had its roots in the Patronage Act of 1712, which required ministers to be put into churches by "the patron", usually the local laird.
Until 1832 this had gone unchallenged.
In that year, the general assembly decided that if a majority of male heads of local families objected to the patron's choice, they had the right of veto.
Ten years of legal argument followed before the House of Lords ruled that the assembly's decision allowing the right to veto was illegal.
Those who accepted the Lords' decision stayed in the Church of Scotland and those who did not left to create the Free Church.
The assembly is meeting at St Columba's Free Church in Edinburgh.
The moderator of this year's assembly is the Reverend David Meredith, minister of Smithton Free Church in Inverness.