diff --git a/plugins/woocommerce-blocks/assets/js/blocks-registry/payment-methods/payment-method-config-helper.ts b/plugins/woocommerce-blocks/assets/js/blocks-registry/payment-methods/payment-method-config-helper.ts
index 3f0868f124d..df56325b76a 100644
--- a/plugins/woocommerce-blocks/assets/js/blocks-registry/payment-methods/payment-method-config-helper.ts
+++ b/plugins/woocommerce-blocks/assets/js/blocks-registry/payment-methods/payment-method-config-helper.ts
@@ -50,6 +50,12 @@ export const canMakePaymentWithExtensions =
 
 			Object.entries( extensionsCallbacks ).forEach(
 				( [ namespace, callbacks ] ) => {
+					if (
+						! ( paymentMethodName in callbacks ) ||
+						typeof callbacks[ paymentMethodName ] !== 'function'
+					) {
+						return;
+					}
 					namespacedCallbacks[ namespace ] =
 						callbacks[ paymentMethodName ];
 				}
diff --git a/plugins/woocommerce-blocks/assets/js/blocks-registry/payment-methods/test/payment-method-config-helper.ts b/plugins/woocommerce-blocks/assets/js/blocks-registry/payment-methods/test/payment-method-config-helper.ts
index 2951725c3d7..4f75083d891 100644
--- a/plugins/woocommerce-blocks/assets/js/blocks-registry/payment-methods/test/payment-method-config-helper.ts
+++ b/plugins/woocommerce-blocks/assets/js/blocks-registry/payment-methods/test/payment-method-config-helper.ts
@@ -88,6 +88,9 @@ describe( 'payment-method-config-helper', () => {
 				woopay: trueCallback,
 				// testpay: one callback errors, one returns true
 				testpay: throwsCallback,
+				// Used to check that only valid callbacks run in each namespace. It is not present in
+				// 'other-woocommerce-marketplace-extension'.
+				blocks_pay: trueCallback,
 			}
 		);
 		registerPaymentMethodExtensionCallbacks(
@@ -202,5 +205,14 @@ describe( 'payment-method-config-helper', () => {
 			expect( throwsCallback ).toHaveBeenCalledTimes( 1 );
 			expect( trueCallback ).toHaveBeenCalledTimes( 1 );
 		} );
+
+		it( 'Does not error when a callback for a payment method is in one namespace but not another', () => {
+			helpers.canMakePaymentWithExtensions(
+				() => true,
+				canMakePaymentExtensionsCallbacks,
+				'blocks_pay'
+			)( canMakePaymentArgument );
+			expect( console ).not.toHaveErrored();
+		} );
 	} );
 } );