Paediatrician Jennifer Cunningham, GP Mike Fitzpatrick, independent social services consultant Maggie Mellon and Scottish Conservative spokeswoman Liz Smith MSP will all take part in a conference in Edinburgh.
The meeting aims to keep the pressure on the government ahead of a looming legal challenge to the legality of its policy.
They argue the plans would undermine the role of parents in favour of government intrusion.
Scottish Conservative young people spokeswoman Liz Smith MSP said: "It fundamentally undermines the role of parents and families because it gives monitoring power to the state. It will inevitably take resources away from the most vulnerable children.
"The more parents find out about this policy the more they object to it, because they believe it will threaten the important level of trust that there should be between parents and health and social care workers and, of course, between parents and teachers.
"It is no surprise that tomorrow's conference and the intention to make a legal challenge have both attracted strong support."
The Scottish Government said the policy was being introduced in accordance with the wishes of parents.
A spokesman added that it would give every child and their family access to the support and advice they needed. He added: "Named persons - usually a health visitor or a senior teacher already known to the family - were first introduced in response to parents' requests for a single point of contact for advice or help when needed, to avoid having to re-tell their story to different services.
"Nothing in the legislation changes parental rights and responsibilities because we know that mothers and fathers are, with a very few exceptions, the best people to raise their children."