diff --git a/src/functionObjects/utilities/areaWrite/areaWrite.C b/src/functionObjects/utilities/areaWrite/areaWrite.C
index 8a6e7b898e..424471ddc7 100644
--- a/src/functionObjects/utilities/areaWrite/areaWrite.C
+++ b/src/functionObjects/utilities/areaWrite/areaWrite.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2019-2022 OpenCFD Ltd.
+    Copyright (C) 2019-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -148,9 +148,6 @@ bool Foam::areaWrite::read(const dictionary& dict)
 
     verbose_ = dict.getOrDefault("verbose", false);
 
-    // All possible area meshes for the given fvMesh region
-    meshes_ = obr().lookupClass<faMesh>();
-
     dict.readIfPresent("areas", selectAreas_);
 
     if (selectAreas_.empty())
@@ -162,19 +159,19 @@ bool Foam::areaWrite::read(const dictionary& dict)
 
             if (available.size())
             {
-                areaName = available.first();
+                areaName = available.front();
             }
         }
 
         if (!areaName.empty())
         {
             selectAreas_.resize(1);
-            selectAreas_.first() = areaName;
+            selectAreas_.front() = areaName;
         }
     }
 
     // Restrict to specified meshes
-    meshes_.filterKeys(selectAreas_);
+    meshes_ = obr().csorted<faMesh>(selectAreas_);
 
     dict.readEntry("fields", fieldSelection_);
     fieldSelection_.uniq();
@@ -188,8 +185,10 @@ bool Foam::areaWrite::read(const dictionary& dict)
         surfaceWriter::formatOptions(dict, writerType)
     );
 
-    for (const word& areaName : meshes_.keys())
+    for (const faMesh& areaMesh : meshes_)
     {
+        const word& areaName = areaMesh.name();
+
         // Define surface writer, but do NOT yet attach a surface
 
         auto surfWriter = surfaceWriter::New(writerType, writerOptions);
@@ -222,9 +221,9 @@ bool Foam::areaWrite::write()
     DynamicList<label> missed(fieldSelection_.size());
 
 
-    for (const word& areaName : meshes_.sortedToc())
+    for (const faMesh& areaMesh : meshes_)
     {
-        const faMesh& areaMesh = *meshes_[areaName];
+        const word& areaName = areaMesh.name();
 
         polySurface* surfptr = surfaces_->getObjectPtr<polySurface>(areaName);
 
diff --git a/src/functionObjects/utilities/areaWrite/areaWrite.H b/src/functionObjects/utilities/areaWrite/areaWrite.H
index 197857ee96..4c26164070 100644
--- a/src/functionObjects/utilities/areaWrite/areaWrite.H
+++ b/src/functionObjects/utilities/areaWrite/areaWrite.H
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2019-2021 OpenCFD Ltd.
+    Copyright (C) 2019-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -128,8 +128,8 @@ class areaWrite
         //- Names of fields to write
         wordRes fieldSelection_;
 
-        //- Pointers to the requested mesh regions
-        HashTable<const faMesh*> meshes_;
+        //- Pointers to the requested mesh regions (sorted)
+        UPtrList<const faMesh> meshes_;
 
         //- Hold intermediate surfaces.
         //  The faMesh has an indirect face list but we require real ones.
diff --git a/src/functionObjects/utilities/vtkWrite/vtkWrite.C b/src/functionObjects/utilities/vtkWrite/vtkWrite.C
index f8e3afc33f..ed322d5180 100644
--- a/src/functionObjects/utilities/vtkWrite/vtkWrite.C
+++ b/src/functionObjects/utilities/vtkWrite/vtkWrite.C
@@ -289,8 +289,9 @@ bool Foam::functionObjects::vtkWrite::write()
     Info<< name() << " output Time: " << time_.timeName() << nl;
 
     label regioni = 0;
-    for (const word& regionName : meshes_.sortedToc())
+    for (const fvMesh& mesh : meshes_)
     {
+        const word& regionName = mesh.name();
         const word& regionDir = polyMesh::regionName(regionName);
 
         auto& meshProxy = meshSubsets_[regioni];
diff --git a/src/functionObjects/utilities/vtkWrite/vtkWrite.H b/src/functionObjects/utilities/vtkWrite/vtkWrite.H
index 68f1f40caf..ac37cf9b34 100644
--- a/src/functionObjects/utilities/vtkWrite/vtkWrite.H
+++ b/src/functionObjects/utilities/vtkWrite/vtkWrite.H
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2017-2022 OpenCFD Ltd.
+    Copyright (C) 2017-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -213,8 +213,8 @@ class vtkWrite
         //- Dictionary of volume selections
         dictionary selection_;
 
-        //- Pointers to the requested mesh regions
-        HashTable<const fvMesh*> meshes_;
+        //- Pointers to the requested mesh regions (sorted)
+        UPtrList<const fvMesh> meshes_;
 
         //- Subsetting for meshes.
         //  Access index according to sorted mesh names.
diff --git a/src/functionObjects/utilities/vtkWrite/vtkWriteUpdate.C b/src/functionObjects/utilities/vtkWrite/vtkWriteUpdate.C
index bcf6fcf90b..45ed8fdc3a 100644
--- a/src/functionObjects/utilities/vtkWrite/vtkWriteUpdate.C
+++ b/src/functionObjects/utilities/vtkWrite/vtkWriteUpdate.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2018-2022 OpenCFD Ltd.
+    Copyright (C) 2018-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -98,10 +98,8 @@ bool Foam::functionObjects::vtkWrite::update()
     vtuMappings_.resize(meshes_.size());
 
     label regioni = 0;
-    for (const word& regionName : meshes_.sortedToc())
+    for (const fvMesh& mesh : meshes_)
     {
-        const fvMesh& mesh = *(meshes_[regionName]);
-
         if (meshSubsets_.set(regioni))
         {
             meshSubsets_[regioni].clear();
@@ -149,29 +147,27 @@ bool Foam::functionObjects::vtkWrite::readSelection(const dictionary& dict)
 {
     meshSubsets_.clear();
     vtuMappings_.clear();
+    meshes_.clear();
     meshState_ = polyMesh::TOPO_CHANGE;
 
-    // All possible meshes
-    meshes_ = time_.lookupClass<fvMesh>();
-
     selectRegions_.clear();
     dict.readIfPresent("regions", selectRegions_);
 
     if (selectRegions_.empty())
     {
         selectRegions_.resize(1);
-        selectRegions_.first() =
+        selectRegions_.front() =
             dict.getOrDefault<word>("region", polyMesh::defaultRegion);
     }
 
     // Restrict to specified meshes
-    meshes_.filterKeys(selectRegions_);
+    meshes_ = time_.csorted<fvMesh>(selectRegions_);
 
     if (meshes_.empty())
     {
         WarningInFunction
-            << "No mesh regions selected for function object " << name()
-            << nl;
+            << "No mesh regions selected for function object "
+            << name() << nl;
     }
 
     selectPatches_.clear();