Bishop William Nolan, of the Church's Justice and Peace Commission, announced their support for the Give Me Five campaign.
Organisations such as the Child Poverty Action Group have been urging the Scottish Government to increase the benefit payment, which is received by most families, by £5 a week.
The campaign comes as Holyrood gets new powers over welfare, including the ability to top up existing benefit payments.
With more than 260,000 youngsters in Scotland growing up in families struggling to make ends meet, supporters argue that a £5 increase in child benefit could remove some 30,000 children from poverty.
Bishop Nolan, the Bishop of Galloway and Bishop President of the Justice and Peace Scotland Commission, made the announcement ahead of the national launch of the Give Me Five campaign on Wednesday.
He said: "For a growing number of children, this is not the Scotland of equality, fairness and opportunity that our politicians tell us they wish to achieve.
"I would urge politicians of all parties to support this initiative and act now to reduce the number of our children for whom poverty is destroying their childhood and stifling their future."
Bishop Nolan will be at the launch of the campaign in Coatbridge, where he will be joined by the Right Rev Dr Derek Browning, Moderator of the General Assembly of the Church of Scotland.
The Church of Scotland has already backed the move, with Dr Browning stating there is a "political, social and moral imperative that we act now to effect change for the good".
He added: "The Church of Scotland stands alongside people of all faith traditions, and none, in the move towards fairness for all our children."
John Dickie, the director of Child Poverty Action Group in Scotland, and Sir Harry Burns, the former chief medical officer for Scotland who is now Professor of Global Public Health at the University of Strathclyde, will also be at the campaign launch.
Polling by Survation found almost two thirds of Scots are in favour of Holyrood increasing child benefits, with 36.2% strongly supporting the move while 28.6% said they were ''somewhat'' in favour.
First Minister Nicola Sturgeon has already told MSPs at Holyrood the "door is not closed" to a benefit top-up.
She spoke after Labour, Tory and Green MSPs on Holyrood's Social Security Committee united in June to vote through a series of amendments to the Scottish Government's Child Poverty Bill - including one by Green MSP Alison Johnstone requiring ministers to set out whether they will use new welfare powers to increase child benefit.
Ms Sturgeon stressed the "bold" legislation would leave Scotland as the only part of the UK with binding targets to reduce child poverty.
Speaking at First Minister's Questions she said: ''I hope we can conclude this Bill and come to an outcome where we all agree that we're doing the best things possible, so the door is not closed to anything that's being suggested."
