diff --git a/ethosu/regor/compiler/graphir_optimiser.cpp b/ethosu/regor/compiler/graphir_optimiser.cpp
index ea1ad4058dd3d1e933a669297755ae526a1b3071..b166a35cff6d25ce3d212f926c2c7e27bada23e1 100644
--- a/ethosu/regor/compiler/graphir_optimiser.cpp
+++ b/ethosu/regor/compiler/graphir_optimiser.cpp
@@ -1872,7 +1872,7 @@ Operation *GraphIrOptimiser::RewriteTransposeConvOFMPadding(Graph *const graph,
         // Create zero-input tensor that has same shape as the padded OFM-area
         std::string inputName = fmt::format("{}_inputZero", name);
         RoundMode rounding;
-        if ( biasType == DataType::Int48 )
+        if ( biasType == DataType::Int48 || biasType == DataType::Int64 )
         {
             auto zeroBuf = std::make_shared<Buffer>(std::vector<int16_t>(sliceElements, 0));
             inputZero = std::make_shared<Tensor>(inputName, DataType::Int16, padSlice.shape, zeroBuf);