Campaign group Fathers 4 Justice has called a truce with the service which advises courts in child custody cases.
Fathers 4 Justice campaigners have staged several high profile stunts
The Children and Family Court Advisory and Support Service (Cafcass) had been among the group's main protest targets.
Cafcass is to issue a statement calling for "constructive dialogue" with the group, which campaigns for fathers' rights.
The campaigners grew in prominence after members dressed as superheroes mounted famous landmarks.
Fathers 4 Justice says it has expelled those members.
Cafcass said the conciliatory tone would aid "public confidence" in them.
Its chief executive, Anthony Douglas, said: "We needed to lower the temperature so that new fathers who came to us didn't perceive, on the back of those kinds of campaigns, that we were biased against them.
"It's very important in our work to have public confidence and confidence from mothers, fathers and other relatives that we're going to be neutral and do best for their children."
The advisory group writes reports on families and recommend who gains custody of children, as well as the amount of access given to the other parent.
In the past Fathers 4 Justice had claimed that Cafcass helped to create an institutional bias towards mothers being given custody of children and too little access to fathers.
A statement expected from Cafcass is also expected to stress the importance of a continuing relationship with both parents in custody cases.
High profile stunts
Matt O'Connor of Fathers 4 Justice called the move "a significant leap in the mindset of Cafcass as an organisation".
"When we first started they said 'what problem?' Now we have them seriously addressing and recognising the rights of children to see their fathers."
Fathers 4 Justice members have conducted a number of high profile stunts, including climbing a wall at Buckingham Palace last September.
And last May Tony Blair was hit by packages of flour thrown by members of the group while speaking in the House of Commons.