The Scottish Secular Society have repeated their call for the religious observance rules in Scotland to be applied on an 'opt in' basis.
Currently, the default position is that Scottish children are expected to attend assemblies and other school events with religious content, unless their parents make specific requests to have them excused.
The new chair of the SSS, Spencer Fildes, called last week for "urgent root and branch reform" of the current system.
"This must not only be applicable to the needs of all stakeholders, including parents, but also be fully and practically implementable, thus permitting religious observance to function meaningfully and appropriately addressing the wishes of all parents by safeguarding, supporting and promoting the well-being of their children," he said.
"This can be easily achieved by simply asking for parental consent."
The initial SSS campaign for these changes centred on a petition submitted in September 2013. But because of the limited moves on the issue since then, the SSS have raised their concerns for a second time.
The SSS complains that children who have opted out of religious observance assemblies have often been told to either sit outside the headmaster's office, or given menial tasks like sharpening pencils.
Data gathered on the subject by YouGov revealed that 40 per cent of Scottish parents did not know opting out of religious observance lessons was an option, while 39 per cent said they did know but had found out through non-school sources.
The SSS argues that the decline in Scottish religious affiliation makes the opt out system of religious observance assemblies something of an anachronism. They point out that between 2001 and 2011 the percentage of those reporting they had no faith increased by 16 per cent to reach 53 per cent of the Scottish population.
The Church of Scotland has however offered strong objections to any potential changes. Reverend Sandy Fraser, Convener of the Church of Scotland Education Committee said: "Religious observance in schools is something that benefits the entire school community and helps give pupils an idea of spirituality.
"It is not about promoting one faith over another. The Church believes that this properly reflects the multicultural, diverse Scotland of the 21st century."
Questioning the fairness of an opt in for religious observance, Rev Fraser said: "It is utterly implausible to imagine parents having to opt in to other cross curricular or whole-school learning activities, such as Personal and Social Development or Physical Education.
"Why should religious observance be treated any differently? Young people have a right to spiritual development which is genuinely inclusive and reflective of the diversity of our nation."
The Church of Scotland has previously cooperated with secular groups on issues surrounding religious observance in schools, such as supporting the lesson's name change from 'religious observance' to 'time for reflection' to make the lesson more inclusive.
The support for the name change caused some controversy within the Church and the Reverend Sally Foster-Fulton, convener of the Church and Society Council of the Church of Scotland later confirmed that the matter would be debated by the Church of Scotland General Assembly in May.
"The Council believes that its recommendation is a more accurate name for what is currently called 'Religious Observance' because since government guidelines in 2005, these assemblies have addressed those who follow Christ and those who do not," she said.
The initial petition to the Scottish Parliament on the issue of a religious observance 'opt in' change gathered 1,516 signatures.