diff --git a/CHANGELOG.md b/CHANGELOG.md
index 80ea0b78..692131b0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **Breaking**: Change `output` parameter of `decode_into` codec trait methods to `&UnsafeCellSlice<u8>`
 - **Breaking**: Add `dynamic()` to all `CodecTraits`
 - **Breaking**: Add `options` parameter to `[Async]ArrayPartialDecoderTraits::partial_decode` and remove `partial_decode_opt`
+- Make `array::update_array_bytes()` public
 
 ## [0.17.1] - 2024-10-18
 
diff --git a/zarrs/src/array.rs b/zarrs/src/array.rs
index c761b55c..6bab57a5 100644
--- a/zarrs/src/array.rs
+++ b/zarrs/src/array.rs
@@ -46,7 +46,10 @@ use std::sync::Arc;
 
 pub use self::{
     array_builder::ArrayBuilder,
-    array_bytes::{copy_fill_value_into, ArrayBytes, ArrayBytesError, RawBytes, RawBytesOffsets},
+    array_bytes::{
+        copy_fill_value_into, update_array_bytes, ArrayBytes, ArrayBytesError, RawBytes,
+        RawBytesOffsets,
+    },
     array_errors::{ArrayCreateError, ArrayError},
     array_metadata_options::ArrayMetadataOptions,
     array_representation::{
diff --git a/zarrs/src/array/array_async_readable_writable.rs b/zarrs/src/array/array_async_readable_writable.rs
index 07805420..cbc6677b 100644
--- a/zarrs/src/array/array_async_readable_writable.rs
+++ b/zarrs/src/array/array_async_readable_writable.rs
@@ -156,13 +156,15 @@ impl<TStorage: ?Sized + AsyncReadableWritableStorageTraits + 'static> Array<TSto
                 .await?;
 
             // Update the chunk
-            let chunk_bytes_new = update_array_bytes(
-                chunk_bytes_old,
-                chunk_shape,
-                chunk_subset_bytes,
-                chunk_subset,
-                self.data_type().size(),
-            );
+            let chunk_bytes_new = unsafe {
+                update_array_bytes(
+                    chunk_bytes_old,
+                    &chunk_shape,
+                    chunk_subset,
+                    chunk_subset_bytes,
+                    self.data_type().size(),
+                )
+            };
 
             // Store the updated chunk
             self.async_store_chunk_opt(chunk_indices, chunk_bytes_new, options)
diff --git a/zarrs/src/array/array_bytes.rs b/zarrs/src/array/array_bytes.rs
index 94de243c..b8eea56c 100644
--- a/zarrs/src/array/array_bytes.rs
+++ b/zarrs/src/array/array_bytes.rs
@@ -10,7 +10,7 @@ use crate::{
     metadata::v3::array::data_type::DataTypeSize,
 };
 
-use super::{codec::CodecError, ravel_indices, ArrayShape, ArraySize, DataType, FillValue};
+use super::{codec::CodecError, ravel_indices, ArraySize, DataType, FillValue};
 
 /// Array element bytes.
 pub type RawBytes<'a> = Cow<'a, [u8]>;
@@ -298,7 +298,7 @@ pub fn update_bytes_flen(
 pub fn update_bytes_vlen<'a>(
     output_bytes: &RawBytes,
     output_offsets: &RawBytesOffsets,
-    output_shape: ArrayShape,
+    output_shape: &[u64],
     subset_bytes: &RawBytes,
     subset_offsets: &RawBytesOffsets,
     subset: &ArraySubset,
@@ -317,7 +317,7 @@ pub fn update_bytes_vlen<'a>(
             .sum::<usize>()
     };
     let size_subset_old = {
-        let chunk_indices = subset.linearised_indices(&output_shape).unwrap();
+        let chunk_indices = subset.linearised_indices(output_shape).unwrap();
         chunk_indices
             .iter()
             .map(|index| {
@@ -333,7 +333,7 @@ pub fn update_bytes_vlen<'a>(
         .checked_sub(size_subset_old)
         .unwrap();
     let mut bytes_new = Vec::with_capacity(bytes_new_len);
-    let indices = ArraySubset::new_with_shape(output_shape).indices();
+    let indices = ArraySubset::new_with_shape(output_shape.to_vec()).indices();
     for (chunk_index, indices) in indices.iter().enumerate() {
         offsets_new.push(bytes_new.len());
         if subset.contains(&indices) {
@@ -358,16 +358,25 @@ pub fn update_bytes_vlen<'a>(
     ArrayBytes::new_vlen(bytes_new, offsets_new)
 }
 
-/// Update the intersecting subset of the chunk
-/// This function is used internally by [`store_chunk_subset_opt`] and [`async_store_chunk_subset_opt`]
-pub fn update_array_bytes<'a>(
+/// Update a subset of an array.
+///
+/// This function is used internally by [`crate::array::Array::store_chunk_subset_opt`] and [`crate::array::Array::async_store_chunk_subset_opt`].
+///
+/// # Safety
+/// The caller must ensure that:
+///  - `output_bytes` is an array with `output_shape` and `data_type_size`,
+///  - `output_subset_bytes` is an array with the shape of `output_subset` and `data_type_size`,
+///  - `output_subset` is within the bounds of `output_shape`, and
+///  - `output_bytes` and `output_subset_bytes` are compatible (e.g. both fixed or both variable sized).
+#[must_use]
+pub unsafe fn update_array_bytes<'a>(
     output_bytes: ArrayBytes,
-    output_shape: ArrayShape,
-    subset_bytes: ArrayBytes,
-    subset: &ArraySubset,
+    output_shape: &[u64],
+    output_subset: &ArraySubset,
+    output_subset_bytes: ArrayBytes,
     data_type_size: DataTypeSize,
 ) -> ArrayBytes<'a> {
-    match (output_bytes, subset_bytes, data_type_size) {
+    match (output_bytes, output_subset_bytes, data_type_size) {
         (
             ArrayBytes::Variable(chunk_bytes, chunk_offsets),
             ArrayBytes::Variable(chunk_subset_bytes, chunk_subset_offsets),
@@ -378,7 +387,7 @@ pub fn update_array_bytes<'a>(
             output_shape,
             &chunk_subset_bytes,
             &chunk_subset_offsets,
-            subset,
+            output_subset,
         ),
         (
             ArrayBytes::Fixed(chunk_bytes),
@@ -390,9 +399,9 @@ pub fn update_array_bytes<'a>(
                 let chunk_bytes = UnsafeCellSlice::new(&mut chunk_bytes);
                 update_bytes_flen(
                     &chunk_bytes,
-                    &output_shape,
+                    output_shape,
                     &chunk_subset_bytes,
-                    subset,
+                    output_subset,
                     data_type_size,
                 );
             }
diff --git a/zarrs/src/array/array_sync_readable_writable.rs b/zarrs/src/array/array_sync_readable_writable.rs
index 7fbeb059..2efb494f 100644
--- a/zarrs/src/array/array_sync_readable_writable.rs
+++ b/zarrs/src/array/array_sync_readable_writable.rs
@@ -185,13 +185,15 @@ impl<TStorage: ?Sized + ReadableWritableStorageTraits + 'static> Array<TStorage>
             chunk_bytes_old.validate(chunk_shape.iter().product(), self.data_type().size())?;
 
             // Update the chunk
-            let chunk_bytes_new = update_array_bytes(
-                chunk_bytes_old,
-                chunk_shape,
-                chunk_subset_bytes,
-                chunk_subset,
-                self.data_type().size(),
-            );
+            let chunk_bytes_new = unsafe {
+                update_array_bytes(
+                    chunk_bytes_old,
+                    &chunk_shape,
+                    chunk_subset,
+                    chunk_subset_bytes,
+                    self.data_type().size(),
+                )
+            };
 
             // Store the updated chunk
             self.store_chunk_opt(chunk_indices, chunk_bytes_new, options)