diff --git a/modules/dnn/src/ocl4dnn/src/ocl4dnn_conv_spatial.cpp b/modules/dnn/src/ocl4dnn/src/ocl4dnn_conv_spatial.cpp
index a1164273ac..45bd249e5d 100644
--- a/modules/dnn/src/ocl4dnn/src/ocl4dnn_conv_spatial.cpp
+++ b/modules/dnn/src/ocl4dnn/src/ocl4dnn_conv_spatial.cpp
@@ -1034,12 +1034,15 @@ bool OCL4DNNConvSpatial<float>::convolve(const UMat &bottom, UMat &top,
         kernel.set(argIdx++, (uint16_t)output_w_);
         kernel.set(argIdx++, (uint16_t)output_h_);
 
-        size_t global_size[3];
-        global_size[0] = output_w_;
-        global_size[1] = output_h_;
-        global_size[2] = num_output_ * num_;
-
-        if (!kernel.run_(3, global_size, NULL, false))
+        size_t wgs = kernel.workGroupSize();
+        if (!wgs)
+        {
+            CV_LOG_ERROR(NULL, "DNN/OpenCL: Can't query workGroupSize of DWCONV kernel");
+            return false;
+        }
+        size_t lws[1] = { wgs };
+        size_t gws[1] = { roundUp((size_t)output_w_ * output_h_ * num_output_ * num_, (unsigned)lws[0]) };
+        if (!kernel.run_(1, gws, lws, false))
         {
             CV_LOG_ERROR(NULL, "DNN/OpenCL: DWCONV kernel run failed");
             return false;
diff --git a/modules/dnn/src/opencl/conv_layer_spatial.cl b/modules/dnn/src/opencl/conv_layer_spatial.cl
index 455f0ed7ea..eb5d354020 100644
--- a/modules/dnn/src/opencl/conv_layer_spatial.cl
+++ b/modules/dnn/src/opencl/conv_layer_spatial.cl
@@ -1850,10 +1850,13 @@ __kernel void DWCONV(
     const ushort output_width,
     const ushort output_height) {
   __global Dtype* convolved_image = convolved_image_base + convolved_image_offset;
-  const int outputX = get_global_id(0);
-  const int outputY = get_global_id(1);
-  const int outputZ = get_global_id(2);
-  if(outputX < output_width && outputY < output_height)
+  const int out_idx = get_global_id(0);  // 1D task layout: [output_width * output_height * OUTPUT_Z]
+  const int plane_size = output_width * output_height;
+  const int out_plane_idx = out_idx % plane_size;
+  const int outputZ = out_idx / plane_size;
+  const int outputY = out_plane_idx / output_width;
+  const int outputX = out_plane_idx % output_width;
+  if (outputZ < OUTPUT_Z)
   {
     Dtype sum = 0.;