diff --git a/internal/contracts/operations.go b/internal/contracts/operations.go
index c308aa51a..cbb9c63e3 100644
--- a/internal/contracts/operations.go
+++ b/internal/contracts/operations.go
@@ -1,4 +1,4 @@
-// Copyright © 2023 Kaleido, Inc.
+// Copyright © 2024 Kaleido, Inc.
 //
 // SPDX-License-Identifier: Apache-2.0
 //
@@ -17,6 +17,7 @@
 package contracts
 
 import (
+	"bytes"
 	"context"
 	"encoding/json"
 
@@ -38,7 +39,9 @@ type blockchainContractDeployData struct {
 func addBlockchainReqInputs(op *core.Operation, req interface{}) (err error) {
 	var reqJSON []byte
 	if reqJSON, err = json.Marshal(req); err == nil {
-		err = json.Unmarshal(reqJSON, &op.Input)
+		d := json.NewDecoder(bytes.NewReader(reqJSON))
+		d.UseNumber()
+		err = d.Decode(&op.Input)
 	}
 	return err
 }
diff --git a/internal/contracts/operations_test.go b/internal/contracts/operations_test.go
index bd425dabc..b3dcb9b4f 100644
--- a/internal/contracts/operations_test.go
+++ b/internal/contracts/operations_test.go
@@ -1,4 +1,4 @@
-// Copyright © 2023 Kaleido, Inc.
+// Copyright © 2024 Kaleido, Inc.
 //
 // SPDX-License-Identifier: Apache-2.0
 //
@@ -16,7 +16,9 @@
 package contracts
 
 import (
+	"bytes"
 	"context"
+	"encoding/json"
 	"fmt"
 	"testing"
 
@@ -35,6 +37,21 @@ import (
 	"github.com/stretchr/testify/mock"
 )
 
+const sampleRequestLargeNumberInput = `{
+	"location": {
+	  "address": "0x1111"
+    },
+	"key": "0x123",
+	"method": {
+      "name": "set",
+      "params": null,
+      "returns": null
+    },
+	"input": {
+	  "value": 10000000000000000000000000001
+	}
+}`
+
 func reqWithMessage(msgType core.MessageType) *core.ContractCallRequest {
 	return &core.ContractCallRequest{
 		Key:      "0x123",
@@ -60,6 +77,7 @@ func reqWithMessage(msgType core.MessageType) *core.ContractCallRequest {
 }
 
 func TestPrepareAndRunBlockchainInvoke(t *testing.T) {
+
 	cm := newTestContractManager()
 
 	op := &core.Operation{
@@ -101,6 +119,46 @@ func TestPrepareAndRunBlockchainInvoke(t *testing.T) {
 	mbi.AssertExpectations(t)
 }
 
+func TestPrepareAndRunBlockchainInvokeLargeNumberInput(t *testing.T) {
+
+	cm := newTestContractManager()
+
+	var req core.ContractCallRequest
+	d := json.NewDecoder(bytes.NewReader([]byte(sampleRequestLargeNumberInput)))
+	d.UseNumber()
+	err := d.Decode(&req)
+	assert.NoError(t, err)
+
+	op := &core.Operation{
+		Type:      core.OpTypeBlockchainInvoke,
+		ID:        fftypes.NewUUID(),
+		Namespace: "ns1",
+	}
+
+	err = addBlockchainReqInputs(op, req)
+	assert.NoError(t, err)
+
+	mbi := cm.blockchain.(*blockchainmocks.Plugin)
+	opaqueData := "anything"
+	mbi.On("ParseInterface", context.Background(), mock.MatchedBy(func(method *fftypes.FFIMethod) bool {
+		return method.Name == req.Method.Name
+	}), req.Errors).Return(opaqueData, nil)
+	mbi.On("InvokeContract", context.Background(), "ns1:"+op.ID.String(), "0x123", mock.MatchedBy(func(loc *fftypes.JSONAny) bool {
+		return loc.String() == req.Location.String()
+	}), opaqueData, req.Input, req.Options, (*blockchain.BatchPin)(nil)).Return(false, nil)
+
+	po, err := cm.PrepareOperation(context.Background(), op)
+	assert.NoError(t, err)
+	assert.Equal(t, &req, po.Data.(txcommon.BlockchainInvokeData).Request)
+
+	_, phase, err := cm.RunOperation(context.Background(), po)
+
+	assert.Equal(t, core.OpPhasePending, phase)
+	assert.NoError(t, err)
+
+	mbi.AssertExpectations(t)
+}
+
 func TestPrepareAndRunBlockchainInvokeRejected(t *testing.T) {
 	cm := newTestContractManager()
 
diff --git a/internal/txcommon/contract_inputs.go b/internal/txcommon/contract_inputs.go
index 942ca6625..9b900f023 100644
--- a/internal/txcommon/contract_inputs.go
+++ b/internal/txcommon/contract_inputs.go
@@ -1,4 +1,4 @@
-// Copyright © 2023 Kaleido, Inc.
+// Copyright © 2024 Kaleido, Inc.
 //
 // SPDX-License-Identifier: Apache-2.0
 //
@@ -17,6 +17,7 @@
 package txcommon
 
 import (
+	"bytes"
 	"context"
 	"encoding/json"
 
@@ -39,7 +40,9 @@ type BlockchainInvokeData struct {
 func RetrieveBlockchainInvokeInputs(ctx context.Context, op *core.Operation) (*core.ContractCallRequest, error) {
 	var req core.ContractCallRequest
 	s := op.Input.String()
-	if err := json.Unmarshal([]byte(s), &req); err != nil {
+	d := json.NewDecoder(bytes.NewReader([]byte(s)))
+	d.UseNumber()
+	if err := d.Decode(&req); err != nil {
 		return nil, i18n.WrapError(ctx, err, i18n.MsgJSONObjectParseFailed, s)
 	}
 	return &req, nil