Sharon Mitchell said the situation was critical and the event was being organised 'to help people enduring terrible hardship and violence, who have lost everything they love and value'.
She volunteered for Calais Light in May, working with migrants in Calais and Dunkirk in conjunction with Care for Calais, Refugee Community Kitchen and Calais Appeal.
Sharon said: "I saw men and women ask volunteers to share in the little food they had. Perhaps we can learn from their generosity and kindness, instead of vilifying them.
"St Mary of the Angels is keen to help the refugee community in France who are in life-threatening situations, exhausted and in need of human support.
"Everyone is welcome at our coffee morning, to enjoy a coffee and cake, take part in our raffle and find out more about the human repercussions of the worldwide refugee crisis. Your donations will help our brothers and sisters in Calais and Dunkirk to feel honoured and to regain their dignity. They will also be able to see that the church family and wider community recognises the loss and pain they have endured."
Coffee for Calais will be held at St Mary of the Angels Catholic Church, in Richmond Road, Worthing, on Saturday, July 9, at 10.45am.
Sharon said: "Calais Light is a small but fierce refugee charity. Launched six years ago, the charity runs convoys from Brentwood to Calais, approximately every three months.
"Ordinary people get the chance to do something concrete and practical to help people stay alive and offer them aid and comfort. Care for Calais and the sister charities receive manpower and money.
"The trips are intergenerational, with a collection of people from different professions and with different life experience. Volunteers are connected by the compassion we feel for the migrant community and the motivation we all have to help. Walking into the refugee’s story, knowing that we are making a difference, changes lives, leaving an indelible imprint in our minds and on our hearts.
"For the refugee community, the truth of their lives is cruel and often brutal. Disparate groups in Calais and Dunkirk live in the shrub on the sand dunes, in tents, real or makeshift. The community consists of young men but also women and small children. Some people have been there for years."