diff --git a/cpp/include/raft/neighbors/detail/ivf_pq_codepacking.cuh b/cpp/include/raft/neighbors/detail/ivf_pq_codepacking.cuh
index 622b911a8f..13da363fd5 100644
--- a/cpp/include/raft/neighbors/detail/ivf_pq_codepacking.cuh
+++ b/cpp/include/raft/neighbors/detail/ivf_pq_codepacking.cuh
@@ -103,11 +103,11 @@ struct bitfield_view_t {
  *    type: void (uint8_t code, uint32_t out_ix, uint32_t j), where j = [0..pq_dim).
  */
 template <uint32_t PqBits, typename Action>
-__device__ void run_on_vector(std::variant<const uint8_t*, list_const_view> in_list_data,
-                              uint32_t in_ix,
-                              uint32_t out_ix,
-                              uint32_t pq_dim,
-                              Action action)
+__host__ __device__ void run_on_vector(std::variant<const uint8_t*, list_const_view> in_list_data,
+                                       uint32_t in_ix,
+                                       uint32_t out_ix,
+                                       uint32_t pq_dim,
+                                       Action action)
 {
   using group_align         = Pow2<kIndexGroupSize>;
   const uint32_t group_ix   = group_align::div(in_ix);
diff --git a/cpp/include/raft/neighbors/ivf_pq_codepacker.cuh b/cpp/include/raft/neighbors/ivf_pq_codepacker.cuh
index 9562a60552..116ced0067 100644
--- a/cpp/include/raft/neighbors/ivf_pq_codepacker.cuh
+++ b/cpp/include/raft/neighbors/ivf_pq_codepacker.cuh
@@ -20,45 +20,67 @@
 #include <raft/core/device_mdspan.hpp>
 #include <raft/core/resource/cuda_stream.hpp>
 #include <raft/core/resources.hpp>
-#include <raft/neighbors/ivf_pq_types.hpp>
-#include <raft/neighbors/detail/ivf_pq_build.cuh>
 #include <raft/neighbors/detail/div_utils.hpp>
+#include <raft/neighbors/detail/ivf_pq_codepacking.cuh>
+#include <raft/neighbors/ivf_pq_types.hpp>
 
 namespace raft::neighbors::ivf_pq::codepacker {
 
-template <uint32_t PqBits>
-void unpack_1(
-  const uint8_t* block, uint8_t* flat_code, uint32_t pq_dim, uint32_t offset)
-{
-  RAFT_EXPECTS(PqBits == 8, "host codepacker supports only PqBits == 8");
-  using group_align = neighbors::detail::div_utils<kIndexGroupSize>;
-  const uint32_t group_ix   = group_align::div(offset);
-  const uint32_t ingroup_ix = group_align::mod(offset);
+/**
+ * A producer for the `write_vector` reads the codes byte-by-byte. That is,
+ * independent of the code width (pq_bits), one code uses the whole byte, hence
+ * one vectors uses pq_dim bytes.
+ */
+struct pass_1_action {
+  const uint8_t* flat_code;
 
-  const uint32_t fixed_offset = group_ix * kIndexGroupSize * pq_dim + ingroup_ix * kIndexGroupVecLen;
+  /**
+   * Create a callable to be passed to `write_vector`.
+   *
+   * @param[in] flat_code flat PQ codes (one byte per code) of a single vector.
+   */
+  __host__ __device__ inline pass_1_action(const uint8_t* flat_code) : flat_code{flat_code} {}
 
-  for (uint32_t j = 0; j < pq_dim; j += kIndexGroupVecLen) {
-    std::memcpy(flat_code + j, block + fixed_offset + (j / kIndexGroupVecLen) * pq_dim, kIndexGroupVecLen);
+  /** Read j-th component (code) of the i-th vector from the source. */
+  __host__ __device__ inline auto operator()(uint32_t i, uint32_t j) const -> uint8_t
+  {
+    return flat_code[j];
   }
-}
+};
+
+/**
+ * A consumer for the `run_on_vector` that just flattens PQ codes
+ * one-per-byte. That is, independent of the code width (pq_bits), one code uses
+ * the whole byte, hence one vectors uses pq_dim bytes.
+ */
+struct unpack_1_action {
+  uint8_t* out_flat_code;
+
+  /**
+   * Create a callable to be passed to `run_on_vector`.
+   *
+   * @param[out] out_flat_code the destination for the read PQ codes of a single vector.
+   */
+  __host__ __device__ inline unpack_1_action(uint8_t* out_flat_code) : out_flat_code{out_flat_code}
+  {
+  }
+
+  /**  Write j-th component (code) of the i-th vector into the output array. */
+  __host__ __device__ inline void operator()(uint8_t code, uint32_t i, uint32_t j)
+  {
+    out_flat_code[j] = code;
+  }
+};
 
 template <uint32_t PqBits>
-void pack_1(
-  const uint8_t* flat_code,
-  uint8_t* block,
-  uint32_t pq_dim,
-  uint32_t offset)
+void unpack_1(const uint8_t* block, uint8_t* flat_code, uint32_t pq_dim, uint32_t offset)
 {
-  RAFT_EXPECTS(PqBits == 8, "host codepacker supports only PqBits == 8");
-  using group_align = neighbors::detail::div_utils<kIndexGroupSize>;
-  const uint32_t group_ix   = group_align::div(offset);
-  const uint32_t ingroup_ix = group_align::mod(offset);
-
-  const uint32_t fixed_offset = group_ix * kIndexGroupSize * pq_dim + ingroup_ix * kIndexGroupVecLen;
+  ivf_pq::detail::run_on_vector<PqBits>(block, offset, 0, pq_dim, unpack_1_action{flat_code});
+}
 
-  for (uint32_t j = 0; j < pq_dim; j += kIndexGroupVecLen) {
-    size_t bytes = min(pq_dim - j, kIndexGroupVecLen);
-      std::memcpy(block + fixed_offset + (j / kIndexGroupVecLen) * pq_dim, flat_code + j, bytes);
-    }
+template <uint32_t PqBits>
+void pack_1(const uint8_t* flat_code, uint8_t* block, uint32_t pq_dim, uint32_t offset)
+{
+  ivf_pq::detail::write_vector<PqBits>(block, offset, 0, pq_dim, pass_1_action{flat_code});
 }
-}  // namespace raft::neighbors::ivf_flat::codepacker
\ No newline at end of file
+}  // namespace raft::neighbors::ivf_pq::codepacker
\ No newline at end of file
diff --git a/cpp/test/neighbors/ann_ivf_pq.cuh b/cpp/test/neighbors/ann_ivf_pq.cuh
index be04d0a686..e03d09ae50 100644
--- a/cpp/test/neighbors/ann_ivf_pq.cuh
+++ b/cpp/test/neighbors/ann_ivf_pq.cuh
@@ -17,7 +17,6 @@
 
 #include "../test_utils.cuh"
 #include "ann_utils.cuh"
-#include "raft/core/logger-macros.hpp"
 #include <raft/core/resource/cuda_stream.hpp>
 
 #include <raft_internal/neighbors/naive_knn.cuh>
@@ -387,7 +386,6 @@ class ivf_pq_test : public ::testing::TestWithParam<ivf_pq_inputs> {
           check_reconstruct_extend(&index, compression_ratio, label);
         } break;
         case 1: {
-          RAFT_LOG_INFO("------PACKING------");
           // Dump and re-write codes for one label
           check_packing(&index, label);
         } break;