diff --git a/src/components/private-name-tag/services/private-name-tag.service.ts b/src/components/private-name-tag/services/private-name-tag.service.ts
index 16664e3b..7f2d3515 100644
--- a/src/components/private-name-tag/services/private-name-tag.service.ts
+++ b/src/components/private-name-tag/services/private-name-tag.service.ts
@@ -15,12 +15,10 @@ import { PrivateNameTagParamsDto } from '../dtos/private-name-tag-params.dto';
 import { PrivateNameTagRepository } from '../repositories/private-name-tag.repository';
 import { CreatePrivateNameTagParamsDto } from '../dtos/create-private-name-tag-params.dto';
 import { GetPrivateNameTagResult } from '../dtos/get-private-name-tag-result.dto';
-import { Not } from 'typeorm';
 import { PrivateNameTag } from '../../../shared/entities/private-name-tag.entity';
 import { UpdatePrivateNameTagParamsDto } from '../dtos/update-private-name-tag-params.dto';
 import { EncryptionService } from '../../encryption/encryption.service';
 import { ServiceUtil } from '../../../shared/utils/service.util';
-import { validate } from 'class-validator';
 
 @Injectable()
 export class PrivateNameTagService {
@@ -64,7 +62,7 @@ export class PrivateNameTagService {
 
   async createNameTag(ctx: RequestContext, req: CreatePrivateNameTagParamsDto) {
     this.logger.log(ctx, `${this.createNameTag.name} was called!`);
-    const errorMsg = await this.validate(req);
+    const errorMsg = await this.validate(ctx.user.id, req);
     if (errorMsg) {
       return errorMsg;
     }
@@ -94,6 +92,11 @@ export class PrivateNameTagService {
     req: UpdatePrivateNameTagParamsDto,
   ) {
     this.logger.log(ctx, `${this.updateNameTag.name} was called!`);
+    const request: CreatePrivateNameTagParamsDto = { ...req, address: '' };
+    const errorMsg = await this.validate(ctx.user.id, request, false);
+    if (errorMsg) {
+      return errorMsg;
+    }
 
     const entity = await this.privateNameTagRepository.findOne(id, {
       where: { createdBy: ctx.user.id },
@@ -141,7 +144,11 @@ export class PrivateNameTagService {
     }
   }
 
-  private async validate(req: CreatePrivateNameTagParamsDto, isCreate = true) {
+  private async validate(
+    user_id: number,
+    req: CreatePrivateNameTagParamsDto,
+    isCreate = true,
+  ) {
     if (isCreate) {
       const validFormat = await this.serviceUtil.isValidBech32Address(
         req.address,
@@ -161,10 +168,10 @@ export class PrivateNameTagService {
       }
 
       // check duplicate address
-      const address = await this.privateNameTagRepository.findOne({
-        where: { address: req.address },
+      const entity = await this.privateNameTagRepository.findOne({
+        where: { createdBy: user_id, address: req.address },
       });
-      if (address) {
+      if (entity) {
         return {
           code: ADMIN_ERROR_MAP.DUPLICATE_ADDRESS.Code,
           message: ADMIN_ERROR_MAP.DUPLICATE_ADDRESS.Message,
@@ -172,6 +179,20 @@ export class PrivateNameTagService {
       }
     }
 
+    // check duplicate private name tag
+    const entity = await this.privateNameTagRepository.findOne({
+      where: {
+        createdBy: user_id,
+        nameTag: await this.encryptionService.encrypt(req.nameTag),
+      },
+    });
+    if (entity) {
+      return {
+        code: ADMIN_ERROR_MAP.DUPLICATE_PRIVATE_TAG.Code,
+        message: ADMIN_ERROR_MAP.DUPLICATE_PRIVATE_TAG.Message,
+      };
+    }
+
     return false;
   }
 
diff --git a/src/shared/constants/common.ts b/src/shared/constants/common.ts
index 401451df..d91ea133 100644
--- a/src/shared/constants/common.ts
+++ b/src/shared/constants/common.ts
@@ -159,6 +159,10 @@ export const ADMIN_ERROR_MAP = {
     Code: 'E002',
     Message: 'Duplicate name tag',
   },
+  DUPLICATE_PRIVATE_TAG: {
+    Code: 'E002',
+    Message: 'Duplicate private name tag',
+  },
   INVALID_FORMAT: {
     Code: 'E003',
     Message: 'Invalid aura address format',