The child/ adolescent is frightened, worried, stressed, doesn't want to see father. You have to sit down and talk to him as only you know why or if the child feels they can with your support as in being by their side to talk and tell the father the reasons then this is the first option.
Second option is depending on the child if they wish they can write a letter, email saying they don't want to and explain why and converse with father so it can be sorted out.
Thirdly, if this doesn't work and many acts to talk or converse with and between the father and the child has resulted in no solution then you will have to either seek family guidance, counselling at Australia Relationships or other family counselling.
This doesn't work, then mediation with a Mediation Process Practioner, you will have to start which by law email 3 practioners' names, address and phone numbers and send it to the father. He has the opportunity to respond within 7 days of his choice out of the 3 practioners to see.
If not, you will chose.
Then the child and yourself depending on the child's age after the appointment is set up will attend mediation. Many attempts will be made to solve and come to agreement. Should this mediation not occur then they will give you a certificate stating that the situation cannot be resolved and that court will be necessary.
You will as well as the child and the father be appointed to a court social worker or counsellor or psychologist who will individually interview you and a family report will be done for court for the judge to view over and discuss between yourself, the ICL and father.
Depending on the age of the child - their view point will be made priority and into consideration but not necessarily given what they want. The older the child from 12-17 of age , the more the judge will take their needs and wants into consideration.
Depending on the reason why they are stressed, don't want to spend time, frightened, the judge can make the father take Tripple P program which is a parenting course, and other orders but the father still has rights to see his child/ children.