diff --git a/pkg/services/rpcsrv/client_test.go b/pkg/services/rpcsrv/client_test.go
index 031dab5ee..d74b83afb 100644
--- a/pkg/services/rpcsrv/client_test.go
+++ b/pkg/services/rpcsrv/client_test.go
@@ -18,6 +18,7 @@ import (
 
 	"github.com/google/uuid"
 	"github.com/gorilla/websocket"
+	"github.com/nspcc-dev/neo-go/internal/basicchain"
 	"github.com/nspcc-dev/neo-go/internal/testchain"
 	"github.com/nspcc-dev/neo-go/pkg/config"
 	"github.com/nspcc-dev/neo-go/pkg/core"
@@ -2499,3 +2500,34 @@ func TestWSClient_SubscriptionsCompat(t *testing.T) {
 		checkRelevant(t, false)
 	})
 }
+
+func TestActor_CallWithNilParam(t *testing.T) {
+	chain, rpcSrv, httpSrv := initServerWithInMemoryChain(t)
+	defer chain.Close()
+	defer rpcSrv.Shutdown()
+
+	c, err := rpcclient.New(context.Background(), httpSrv.URL, rpcclient.Options{})
+	require.NoError(t, err)
+	acc, err := wallet.NewAccount()
+	require.NoError(t, err)
+	act, err := actor.New(c, []actor.SignerAccount{
+		{
+			Signer: transaction.Signer{
+				Account: acc.ScriptHash(),
+			},
+			Account: acc,
+		},
+	})
+	require.NoError(t, err)
+
+	rubles, err := chain.GetContractScriptHash(basicchain.RublesContractID)
+	require.NoError(t, err)
+
+	// We don't have a suitable contract, thus use Rubles with simple put method,
+	// it should fail at the moment of conversion Null value to ByteString (not earlier,
+	// and that's the point of the test!).
+	res, err := act.Call(rubles, "putValue", "123", (*util.Uint160)(nil))
+	require.NoError(t, err)
+
+	require.True(t, strings.Contains(res.FaultException, "invalid conversion: Null/ByteString"), res.FaultException)
+}
diff --git a/pkg/services/rpcsrv/params/txBuilder.go b/pkg/services/rpcsrv/params/txBuilder.go
index 9872c7cc6..9d2c9ea2d 100644
--- a/pkg/services/rpcsrv/params/txBuilder.go
+++ b/pkg/services/rpcsrv/params/txBuilder.go
@@ -84,7 +84,7 @@ func ExpandArrayIntoScript(script *io.BinWriter, slice []Param) error {
 				return err
 			}
 		case smartcontract.AnyType:
-			if fp.Value.IsNull() {
+			if fp.Value.IsNull() || len(fp.Value.RawMessage) == 0 {
 				emit.Opcodes(script, opcode.PUSHNULL)
 			}
 		default: