Unison Scotland is concerned about the ruling, which it believes hinders social workers from acting swiftly and unilaterally in the best interests of children if it conflicts with an existing court order.
The case concerns two social workers who are employed by City of Edinburgh Council and were found guilty of contempt of court after stopping a mother's contact with her children, despite an earlier court ruling that she was entitled to it.
One of the workers, Carol McCulloch, decided to cease contact due to concern the two children were suffering. Her line manager, Gillian Lawrence, approved the decision.
Both were held individually responsible and face court costs thought likely to run into five figures.
Dave Watson, Unison's Scottish organiser, said that they would be seeking a legislative review from ministers about social workers' position in law as a "matter of urgency".
"Social work staff deal with complex and challenging cases on a daily basis and this decision merely muddies the water and puts those working on the frontline in a very difficult and vulnerable position," he said.
"The fact that individuals, rather than the organisation they work for, have been put in this position has wide-ranging implications for the employer/employee relationship and could have a ripple effect on all frontline work."
Sheriff Katherine Mackie initiated proceedings for contempt against the two social workers after her own ruling from May 24 this year was disregarded. She had ruled in favour of a mother, who cannot be named for legal reasons, at appeal, after a children's hearing had reduced her contact with her children, who were in care.
But Ms McCulloch ceased the weekly contact from July 15 until August 22. In her judgment, Sheriff Mackie concluded she had done so without getting legal advice.
Sheriff Mackie said social workers had to comply with court orders and had "no authority to act unilaterally, however strongly held their views may be".
John Stevens, of Unison's City of Edinburgh branch dismissed any notion that social workers could swiftly get another court order to protection at risk children if they had concerns.
He said in the case of Ms McCulloch and Ms Lawrence, the order made by the sheriff was a 'substitution' of a decision of a children's hearing on appeal.
"As such, social workers are not party to the appeal to the sheriff - that is between the Children's Panel and the parent - and have no route to take the issue back to court.
"The only thing they can do is call an urgent review children's hearing, which is what they did," said Mr Stevens.
Any attempt to get a child protection order from a sheriff in such a situation required a "very high level of concern of 'significant harm' and that it was 'urgent and necessary'", he said.
"They are usually sought when a child is in immediate danger in order to remove the child from home, not in cases where the child is already in care. Such an order would not be appropriate, or likely to be granted, in cases of emotional harm being experienced by a child who is already in care."
A Scottish Government spokesman said: "We expect all those working with vulnerable children to place the child at the centre of decision-making.
"We have offered to work with City of Edinburgh Council, the Association of Directors of Social Work and others on any wider learning and follow-up."