Controversial plans to appoint a specific guardian for every child have been branded a "snooper's charter" by a former church leader.
The Rev Dr John Ross, a former moderator of the Free Church of Scotland, said plans to have a named person for every single youngster were "the sort of thing we would expect in a fascist or Marxist regime, not in 21st century Scotland".
He is one of seven leading figures from the Free Church who have taken the unusual step of writing to First Minister Alex Salmond, urging him to amend the legislation and "restore some common sense".
The Scottish Government's proposals for every child to have a named person appointed for them are include in the Children and Young People (Scotland) Bill, which is expected to gain its final approval at Holyrood next week.
The Bill proposes that a named person, such as a health worker or a head teacher, would be responsible for safeguarding a child's welfare and liaising with their family.
The group of leading figures from the Free Church - who include the current moderator the Reverend Angus Howat and six former moderators - are the latest to voice concerns about the move.
The Law Society of Scotland has already warned it could interfere with respect for family and private life, and conflict with human rights, while the Faculty of Advocates said the legislation included an "'indiscriminate provision for possible interference in the lives of all children''.
A Scottish Government spokesman explained the move is aimed at offering families "early support, with a single point of contact, to help prevent emerging concerns becoming more acute"
But Dr Ross, a minister in Drumnadrochit in the Highlands, said: "The Scottish Government now seems intent on hijacking the legitimate rights and duties of parents to bring up their own children free of state interference.
"If this legislation is not amended, the Scottish Government will make itself the judge of every parent in this land."
He added: "Too much power will be given to the discretion of professionals, some of who have never raised a family of their own and many of whom are already stretched to the absolute limit.
"There is also a very real possibility that this legislation could be used as a back door means to completely undermine parental values, judgement and discretion for their own children."
He urged Mr Salmond to "do everything in his power to get rid of this snooper's charter and restore some common sense".
Reverend James MacIver, another former moderator who has signed the letter, stated: "We want the very best for all Scotland's children and are fully supportive of the Scottish Government's intention to improve outcomes for our most vulnerable children, but this does not warrant such a gross intrusion into every home in the country.
"Given that the vast majority of Scotland's million children do not require any state intervention, and the resulting costs of setting up such a scheme, surely the Scottish Government would be better investing in more community nurses and social workers to provide help at a grassroots level for those who are really struggling."
In their letter to Mr Salmond, the churchmen said they were "wary of the statutory appointment of a named person for every under-18 in Scotland".
They argued: "The potential for unnecessary interference would be removed if the legislation made explicit that the named person had no right to be proactive but was available to be called upon by parents to help them access services and support."
A Scottish Government spokesman said: "We have been consistently clear that parents are the best people to bring up their children - but sadly not all children come from safe, secure and loving homes.
"These plans, backed by teachers, health workers and other childcare professionals, aim to promote the well-being of all of Scotland's children, including protecting vulnerable young people who may be experiencing difficulties or at risk of neglect or abuse.
"To be clear, the named person cannot require parents to bring up children in a certain way.
"Professionals and parents may identify where concerns about a child's well-being are emerging and the named person can offer initial help, but the parent is under no obligation to engage with the named person or the service offered.
"If a concern escalates then child protection or other procedures may have to be activated, as is the case currently. But the aim - just as it is with existing schemes already running successfully in parts of Scotland - is to offer families early support, with a single point of contact, to help prevent emerging concerns becoming more acute.
"That contact will almost always be already known to the family, usually a health visitor in the child's earliest years or most commonly a school head or senior teacher."
Bill Alexander, the director of health and social care at Highland Council, said the named person system was already operating "effectively" there.
He said: "The named person role has been operating in Highland for a number of years. It was not introduced at first by the Scottish Government, but developed from practice, from the request from families to have a clear point of contact with services.
"It operates effectively, and enables agencies to respond more quickly to parents who raise concerns about their child's wellbeing."
But Liz Smith, Scottish Conservative spokeswoman for young people, said: "The named person part of this legislation will be open to all kinds of legal challenges.
"That's the strong advice given in evidence to organisations like the Law Society, Faculty of Advocates and the Scottish Parent Teacher Council.
"Parental responsibility and the right to a family life is enshrined in law, and the creation of a named person for every young person in Scotland would bring that into question."
Anne Houston, chief executive of charity Children 1st, said: "Children 1st supports the idea of the named person.
"We are concerned at some of the language being used in these interventions and ask whether if people and organisations were perhaps to approach this more from the perspective of what children need in their lives we may find more common ground.
"Unfortunately not every child can rely on their parent or carer to always act in their best interests, and we know that some vulnerable children can and do slip through the net, sometimes with tragic consequences.
"We also know how confusing it can be for parents and carers who do want to seek advice and help to find their way through the myriad of processes and agencies.
"Having a single point of contact for families is a good thing and is in fact working very well in many parts of the country already. If we focus on putting children's needs and interests first, then it becomes more obvious that having a named person at every stage of a child's life could make a big difference, with parents feeling more like partners in their relationships with agencies, rather than less so."