diff --git a/fsl/wrappers/wrapperutils.py b/fsl/wrappers/wrapperutils.py
index e895eb137822f7129f03f0906281567fdd01e376..16d231d2d539d49c66582a7fe641410c7150ddf5 100644
--- a/fsl/wrappers/wrapperutils.py
+++ b/fsl/wrappers/wrapperutils.py
@@ -721,7 +721,15 @@ class _FileOrThing(object):
 
             # Assumed to be an input file
             else:
-                infile = self.__prepIn(workdir, name, val)
+                if isinstance(val, (list, tuple)):
+                    infile = list(val)
+                    for i, v in enumerate(val):
+                        v = self.__prepIn(workdir, name, v)
+                        if v is not None:
+                            infile[i] = v
+
+                else:
+                    infile = self.__prepIn(workdir, name, val)
 
                 if infile is not None:
                     allargs[name] = infile