diff --git a/src/pytrexio.i b/src/pytrexio.i
index 1503382..f19cb6d 100644
--- a/src/pytrexio.i
+++ b/src/pytrexio.i
@@ -65,12 +65,15 @@
 import_array();
 %}
 
+/* Typemaps below change the type of numpy array dimensions from int to int64_t */
+%numpy_typemaps(double, NPY_DOUBLE, int64_t)
+%numpy_typemaps(int32_t, NPY_INT, int64_t)
 /* Enable write|read_safe functions to convert numpy arrays from/to double arrays */
-%apply (double* ARGOUT_ARRAY1, int DIM1) {(double * const dset_out, const int64_t dim_out)};
-%apply (double* IN_ARRAY1, int DIM1) {(const double * dset_in, const int64_t dim_in)};
+%apply (double* ARGOUT_ARRAY1, int64_t DIM1) {(double * const dset_out, const int64_t dim_out)};
+%apply (double* IN_ARRAY1, int64_t DIM1) {(const double * dset_in, const int64_t dim_in)};
 /* Enable write|read_safe functions to convert numpy arrays from/to int32 arrays */
-%apply (int* ARGOUT_ARRAY1, int DIM1) {(int32_t * const dset_out, const int64_t dim_out)};
-%apply (int* IN_ARRAY1, int DIM1) {(const int32_t * dset_in, const int64_t dim_in)};
+%apply (int32_t* ARGOUT_ARRAY1, int64_t DIM1) {(int32_t * const dset_out, const int64_t dim_out)};
+%apply (int32_t* IN_ARRAY1, int64_t DIM1) {(const int32_t * dset_in, const int64_t dim_in)};
 
 /* This tells SWIG to treat char ** dset_in pattern as a special case 
    Enables access to trexio_[...]_write_dset_str set of functions directly, i.e.