Christian volunteers ministering to pop-up communities in Calais say vicars and pastors need repeat reminders to take the issue seriously.
The faith-based charity Seeking Sanctuary estimates that 800 migrants are currently living in the port town, 15 months since a make-shift settlement dubbed the Jungle was cleared.
Co-director Ben Bano, told Premier: "This issue is getting a little stale for some people.
"It's difficult to get the kind of interest that was around last year, or certainly the year before, because people have almost got used to the situation; there's a degree of donor fatigue."
Tensions between French and British authorities have been rising since the Mayor of Calais Natacha Bouchart demanded that the UK accept more migrants.
The French president visited a migrant centre near Calais on Tuesday, as he prepared to urge Britain to do more to help cope with people converging on the area.
During his first official visit to the UK, Emmanuel Macron will discuss with Prime Minister Theresa May a proposal that would effectively put the British border in Calais.
Seeking Sanctuary also praised plans by the Church of England's Diocese of Canterbury to have a chaplain based in Calais.
Ben Bano added: "Clearly, there are exceptions; there are some churches which really do their bit... but we do have to keep reminding churches and particularly church leaders to speak out on these issues as much as they were doing a year or two years before.
"Their voices aren't lost but it's important they continue."
Click here to listen to Premier's Alex Williams speaking with Ben Bano at Seeking Sanctuary:
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