diff --git a/pandas/_libs/tslibs/conversion.pyx b/pandas/_libs/tslibs/conversion.pyx
index fb77e2b5f3a0c..00e2c8b8b6be6 100644
--- a/pandas/_libs/tslibs/conversion.pyx
+++ b/pandas/_libs/tslibs/conversion.pyx
@@ -40,7 +40,6 @@ from pandas._libs.tslibs.np_datetime cimport (
     NPY_FR_ns,
     astype_overflowsafe,
     check_dts_bounds,
-    dt64_to_dtstruct,
     dtstruct_to_dt64,
     get_datetime64_unit,
     get_datetime64_value,
@@ -248,7 +247,7 @@ cdef _TSObject convert_to_tsobject(object ts, tzinfo tz, str unit,
     elif is_datetime64_object(ts):
         obj.value = get_datetime64_nanos(ts)
         if obj.value != NPY_NAT:
-            dt64_to_dtstruct(obj.value, &obj.dts)
+            pandas_datetime_to_datetimestruct(obj.value, NPY_FR_ns, &obj.dts)
     elif is_integer_object(ts):
         try:
             ts = <int64_t>ts
@@ -266,7 +265,7 @@ cdef _TSObject convert_to_tsobject(object ts, tzinfo tz, str unit,
 
             ts = ts * cast_from_unit(None, unit)
             obj.value = ts
-            dt64_to_dtstruct(ts, &obj.dts)
+            pandas_datetime_to_datetimestruct(ts, NPY_FR_ns, &obj.dts)
     elif is_float_object(ts):
         if ts != ts or ts == NPY_NAT:
             obj.value = NPY_NAT
@@ -289,7 +288,7 @@ cdef _TSObject convert_to_tsobject(object ts, tzinfo tz, str unit,
 
             ts = cast_from_unit(ts, unit)
             obj.value = ts
-            dt64_to_dtstruct(ts, &obj.dts)
+            pandas_datetime_to_datetimestruct(ts, NPY_FR_ns, &obj.dts)
     elif PyDateTime_Check(ts):
         return convert_datetime_to_tsobject(ts, tz, nanos)
     elif PyDate_Check(ts):
diff --git a/pandas/_libs/tslibs/np_datetime.pxd b/pandas/_libs/tslibs/np_datetime.pxd
index 2f775912da141..290483a741fe7 100644
--- a/pandas/_libs/tslibs/np_datetime.pxd
+++ b/pandas/_libs/tslibs/np_datetime.pxd
@@ -76,7 +76,6 @@ cdef bint cmp_scalar(int64_t lhs, int64_t rhs, int op) except -1
 cdef check_dts_bounds(npy_datetimestruct *dts, NPY_DATETIMEUNIT unit=?)
 
 cdef int64_t dtstruct_to_dt64(npy_datetimestruct* dts) nogil
-cdef void dt64_to_dtstruct(int64_t dt64, npy_datetimestruct* out) nogil
 
 cdef int64_t pydatetime_to_dt64(datetime val, npy_datetimestruct *dts)
 cdef void pydatetime_to_dtstruct(datetime dt, npy_datetimestruct *dts)
diff --git a/pandas/_libs/tslibs/np_datetime.pyx b/pandas/_libs/tslibs/np_datetime.pyx
index 24ba329120a51..1aab5dcd6f70b 100644
--- a/pandas/_libs/tslibs/np_datetime.pyx
+++ b/pandas/_libs/tslibs/np_datetime.pyx
@@ -217,14 +217,6 @@ cdef inline int64_t dtstruct_to_dt64(npy_datetimestruct* dts) nogil:
     return npy_datetimestruct_to_datetime(NPY_FR_ns, dts)
 
 
-cdef inline void dt64_to_dtstruct(int64_t dt64,
-                                  npy_datetimestruct* out) nogil:
-    """Convenience function to call pandas_datetime_to_datetimestruct
-    with the by-far-most-common frequency NPY_FR_ns"""
-    pandas_datetime_to_datetimestruct(dt64, NPY_FR_ns, out)
-    return
-
-
 # just exposed for testing at the moment
 def py_td64_to_tdstruct(int64_t td64, NPY_DATETIMEUNIT unit):
     cdef:
diff --git a/pandas/_libs/tslibs/period.pyx b/pandas/_libs/tslibs/period.pyx
index 0fa85f54944eb..e187df6d6f627 100644
--- a/pandas/_libs/tslibs/period.pyx
+++ b/pandas/_libs/tslibs/period.pyx
@@ -49,8 +49,6 @@ from pandas._libs.tslibs.np_datetime cimport (
     NPY_FR_us,
     astype_overflowsafe,
     check_dts_bounds,
-    dt64_to_dtstruct,
-    dtstruct_to_dt64,
     get_timedelta64_value,
     npy_datetimestruct,
     npy_datetimestruct_to_datetime,
@@ -813,7 +811,7 @@ cdef void get_date_info(int64_t ordinal, int freq, npy_datetimestruct *dts) nogi
 
     pandas_datetime_to_datetimestruct(unix_date, NPY_FR_D, dts)
 
-    dt64_to_dtstruct(nanos, &dts2)
+    pandas_datetime_to_datetimestruct(nanos, NPY_DATETIMEUNIT.NPY_FR_ns, &dts2)
     dts.hour = dts2.hour
     dts.min = dts2.min
     dts.sec = dts2.sec
@@ -1149,7 +1147,7 @@ cdef int64_t period_ordinal_to_dt64(int64_t ordinal, int freq) except? -1:
     get_date_info(ordinal, freq, &dts)
 
     check_dts_bounds(&dts)
-    return dtstruct_to_dt64(&dts)
+    return npy_datetimestruct_to_datetime(NPY_DATETIMEUNIT.NPY_FR_ns, &dts)
 
 
 cdef str period_format(int64_t value, int freq, object fmt=None):
diff --git a/pandas/_libs/tslibs/vectorized.pyx b/pandas/_libs/tslibs/vectorized.pyx
index 598127b0eae7c..b63b4cf1df66b 100644
--- a/pandas/_libs/tslibs/vectorized.pyx
+++ b/pandas/_libs/tslibs/vectorized.pyx
@@ -30,7 +30,6 @@ from .nattype cimport (
 from .np_datetime cimport (
     NPY_DATETIMEUNIT,
     NPY_FR_ns,
-    dt64_to_dtstruct,
     npy_datetimestruct,
     pandas_datetime_to_datetimestruct,
 )