diff --git a/python/core/auto_generated/qgsspatialindexkdbush.sip.in b/python/core/auto_generated/qgsspatialindexkdbush.sip.in
index a698091f897..af8178bb327 100644
--- a/python/core/auto_generated/qgsspatialindexkdbush.sip.in
+++ b/python/core/auto_generated/qgsspatialindexkdbush.sip.in
@@ -58,6 +58,7 @@ that of the spatial index construction.
 Any non-single point features encountered during iteration will be ignored and not included in the index.
 %End
 
+
     QgsSpatialIndexKDBush( const QgsSpatialIndexKDBush &other );
 %Docstring
 Copy constructor
diff --git a/src/core/qgsspatialindexkdbush.cpp b/src/core/qgsspatialindexkdbush.cpp
index 93be1eba451..4b5f32922e0 100644
--- a/src/core/qgsspatialindexkdbush.cpp
+++ b/src/core/qgsspatialindexkdbush.cpp
@@ -32,6 +32,11 @@ QgsSpatialIndexKDBush::QgsSpatialIndexKDBush( const QgsFeatureSource &source, Qg
 {
 }
 
+QgsSpatialIndexKDBush::QgsSpatialIndexKDBush( QgsFeatureIterator &fi, const std::function<bool ( const QgsFeature & )> &callback, QgsFeedback *feedback )
+  : d( new QgsSpatialIndexKDBushPrivate( fi, callback, feedback ) )
+{
+}
+
 QgsSpatialIndexKDBush::QgsSpatialIndexKDBush( const QgsSpatialIndexKDBush &other ): d( other.d )
 {
   d->ref.ref();
diff --git a/src/core/qgsspatialindexkdbush.h b/src/core/qgsspatialindexkdbush.h
index 3574855f825..470af854946 100644
--- a/src/core/qgsspatialindexkdbush.h
+++ b/src/core/qgsspatialindexkdbush.h
@@ -23,6 +23,7 @@ class QgsFeedback;
 class QgsFeatureSource;
 class QgsSpatialIndexKDBushPrivate;
 class QgsRectangle;
+class QgsFeature;
 
 #include "qgis_core.h"
 #include "qgsspatialindexkdbushdata.h"
@@ -76,6 +77,28 @@ class CORE_EXPORT QgsSpatialIndexKDBush
      */
     explicit QgsSpatialIndexKDBush( const QgsFeatureSource &source, QgsFeedback *feedback = nullptr );
 
+#ifndef SIP_RUN
+
+    /**
+     * Constructor - creates KDBush index and bulk loads it with features from the source.
+     *
+     * This constructor allows for a \a callback function to be specified, which is
+     * called for each added feature in turn. It allows for bulk spatial index load along with other feature
+     * based operations on a single iteration through a feature source. If \a callback returns FALSE, the
+     * load and iteration is canceled.
+     *
+     * The optional \a feedback object can be used to allow cancellation of bulk feature loading. Ownership
+     * of \a feedback is not transferred, and callers must take care that the lifetime of feedback exceeds
+     * that of the spatial index construction.
+     *
+     * Any non-single point features encountered during iteration will be ignored and not included in the index.
+     *
+     * \note Not available in Python bindings
+     * \since QGIS 3.22
+     */
+    explicit QgsSpatialIndexKDBush( QgsFeatureIterator &fi, const std::function< bool( const QgsFeature & ) > &callback, QgsFeedback *feedback = nullptr );
+#endif
+
     //! Copy constructor
     QgsSpatialIndexKDBush( const QgsSpatialIndexKDBush &other );
 
diff --git a/src/core/qgsspatialindexkdbush_p.h b/src/core/qgsspatialindexkdbush_p.h
index adc71c968fc..b8ef8e985d5 100644
--- a/src/core/qgsspatialindexkdbush_p.h
+++ b/src/core/qgsspatialindexkdbush_p.h
@@ -39,25 +39,26 @@
 #include <memory>
 #include <QList>
 #include "kdbush.hpp"
+#include <functional>
 
 
 class PointXYKDBush : public kdbush::KDBush< std::pair<double, double>, QgsSpatialIndexKDBushData, std::size_t >
 {
   public:
 
-    explicit PointXYKDBush( QgsFeatureIterator &fi, QgsFeedback *feedback = nullptr )
+    explicit PointXYKDBush( QgsFeatureIterator &fi, QgsFeedback *feedback = nullptr, const std::function< bool( const QgsFeature & ) > *callback = nullptr )
     {
-      fillFromIterator( fi, feedback );
+      fillFromIterator( fi, feedback, callback );
     }
 
     explicit PointXYKDBush( const QgsFeatureSource &source, QgsFeedback *feedback )
     {
       points.reserve( source.featureCount() );
       QgsFeatureIterator it = source.getFeatures( QgsFeatureRequest().setNoAttributes() );
-      fillFromIterator( it, feedback );
+      fillFromIterator( it, feedback, nullptr );
     }
 
-    void fillFromIterator( QgsFeatureIterator &fi, QgsFeedback *feedback = nullptr )
+    void fillFromIterator( QgsFeatureIterator &fi, QgsFeedback *feedback = nullptr, const std::function< bool( const QgsFeature & ) > *callback = nullptr )
     {
       std::size_t size = 0;
 
@@ -67,6 +68,9 @@ class PointXYKDBush : public kdbush::KDBush< std::pair<double, double>, QgsSpati
         if ( feedback && feedback->isCanceled() )
           return;
 
+        if ( callback && !( *callback )( f ) )
+          return;
+
         if ( !f.hasGeometry() )
           continue;
 
@@ -109,6 +113,10 @@ class QgsSpatialIndexKDBushPrivate
       : index( std::make_unique < PointXYKDBush >( source, feedback ) )
     {}
 
+    explicit QgsSpatialIndexKDBushPrivate( QgsFeatureIterator &fi, const std::function< bool( const QgsFeature & ) > &callback, QgsFeedback *feedback = nullptr )
+      : index( std::make_unique < PointXYKDBush >( fi, feedback, &callback ) )
+    {}
+
     QAtomicInt ref = 1;
     std::unique_ptr< PointXYKDBush > index;
 };