diff --git a/packages/openapi-2-kong/src/declarative-config/fixtures/nullable-true.expected.json b/packages/openapi-2-kong/src/declarative-config/fixtures/nullable-true.expected.json
new file mode 100644
index 0000000000..ef1f7b9dc4
--- /dev/null
+++ b/packages/openapi-2-kong/src/declarative-config/fixtures/nullable-true.expected.json
@@ -0,0 +1,65 @@
+{
+    "_format_version": "1.1",
+    "services": [
+        {
+            "name": "cktest_cards_api",
+            "protocol": "https",
+            "host": "alb-dev01.openapi-test.merlin",
+            "port": 443,
+            "path": "/",
+            "plugins": [],
+            "routes": [
+                {
+                    "tags": [
+                        "OAS3_import",
+                        "OAS3file_nullable-true.yaml"
+                    ],
+                    "name": "cktest_cards_api-get_api1",
+                    "methods": [
+                        "GET"
+                    ],
+                    "paths": [
+                        "/cktest/cktest_cards/api1$"
+                    ],
+                    "strip_path": false
+                },
+                {
+                    "tags": [
+                        "OAS3_import",
+                        "OAS3file_nullable-true.yaml"
+                    ],
+                    "name": "cktest_cards_api-post_api1",
+                    "methods": [
+                        "POST"
+                    ],
+                    "paths": [
+                        "/cktest/cktest_cards/api1$"
+                    ],
+                    "strip_path": false,
+                    "plugins": [
+                        {
+                            "name": "request-validator",
+                            "config": {
+                                "version": "draft4",
+                                "body_schema": "{\"type\":\"object\",\"title\":\"request-body-nullable\",\"description\":\"This object is sent in post application request.\",\"required\":[\"redirectUri\"],\"properties\":{\"redirectUri\":{\"type\":[\"string\",\"null\"],\"nullable\":true}}}",
+                                "allowed_content_types": [
+                                    "application/json"
+                                ],
+                                "verbose_response": true
+                            },
+                            "tags": [
+                                "OAS3_import",
+                                "OAS3file_nullable-true.yaml"
+                            ],
+                            "enabled": true
+                        }
+                    ]
+                }
+            ],
+            "tags": [
+                "OAS3_import",
+                "OAS3file_nullable-true.yaml"
+            ]
+        }
+    ]
+}
diff --git a/packages/openapi-2-kong/src/declarative-config/fixtures/nullable-true.yaml b/packages/openapi-2-kong/src/declarative-config/fixtures/nullable-true.yaml
new file mode 100644
index 0000000000..9df0894d2c
--- /dev/null
+++ b/packages/openapi-2-kong/src/declarative-config/fixtures/nullable-true.yaml
@@ -0,0 +1,59 @@
+openapi: '3.0.2'
+x-kong-name: cktest_cards_api
+info:
+  title: FTI-3278 Test
+  version: '1.0'
+  description: A sample API specification for FTI-3278
+  contact:
+    email: support@insomnia.rest
+
+servers:
+- url: https://alb-dev01.openapi-test.merlin/
+
+tags:
+  - name: oauth2-credential-flow
+
+paths:
+  /cktest/cktest_cards/api1:
+    get:
+      description: test oauth2
+      operationId: get_api1
+      tags:
+        - oauth2-credential-flow
+
+      responses:
+        '200':
+          description: OK
+
+    post:
+      description: test oauth2
+      operationId: post_api1
+      x-kong-plugin-request-validator:
+        enabled: true
+        config:
+          verbose_response: true
+      requestBody:
+        content:
+          application/json:
+            schema:
+              "$ref": "#/components/schemas/request-body-nullable"
+      responses:
+        '200':
+          description: OK
+
+      tags:
+        - oauth2-credential-flow
+
+
+components:
+  schemas:
+    request-body-nullable:
+      type: object
+      title: request-body-nullable
+      description: This object is sent in post application request.
+      required:
+        - redirectUri
+      properties:
+        redirectUri:
+          type: string
+          nullable: true
diff --git a/packages/openapi-2-kong/src/declarative-config/plugins.test.ts b/packages/openapi-2-kong/src/declarative-config/plugins.test.ts
index adf7b9be4e..5155e7e460 100644
--- a/packages/openapi-2-kong/src/declarative-config/plugins.test.ts
+++ b/packages/openapi-2-kong/src/declarative-config/plugins.test.ts
@@ -1,7 +1,7 @@
 import { ParameterSchema, RequestTerminationPlugin, RequestValidatorPlugin, xKongPluginKeyAuth, xKongPluginRequestTermination, xKongPluginRequestValidator } from '../types/kong';
 import { OA3Operation, OA3Parameter } from '../types/openapi3';
 import { getSpec, pluginDummy, tags, UserDCPlugin } from './jest/test-helpers';
-import { ALLOW_ALL_SCHEMA, generateGlobalPlugins, generateRequestValidatorPlugin } from './plugins';
+import { ALLOW_ALL_SCHEMA, generateBodyOptions, generateGlobalPlugins, generateRequestValidatorPlugin } from './plugins';
 
 describe('plugins', () => {
   describe('generateGlobalPlugins()', () => {
@@ -393,5 +393,63 @@ describe('plugins', () => {
         });
       });
     });
+    describe('body_schema generateBodyOptions FTI-3278', () => {
+      it('should keep to properties[].type unchanged nullable is not set', () => {
+        const generated = generateBodyOptions({
+          requestBody: {
+            content: {
+              'application/json': {
+                schema: {
+                  properties: {
+                    redirectUri: {
+                      type: 'string',
+                    },
+                  },
+                },
+              },
+            },
+          },
+        });
+        expect(generated.bodySchema).toStrictEqual('{\"properties\":{\"redirectUri\":{\"type\":\"string\"}}}');
+      });
+      it('should keep to properties[].type unchanged nullable is false', () => {
+        const generated = generateBodyOptions({
+          requestBody: {
+            content: {
+              'application/json': {
+                schema: {
+                  properties: {
+                    redirectUri: {
+                      type: 'string',
+                      nullable: false,
+                    },
+                  },
+                },
+              },
+            },
+          },
+        });
+        expect(generated.bodySchema).toStrictEqual('{\"properties\":{\"redirectUri\":{\"type\":\"string\",\"nullable\":false}}}');
+      });
+      it('should append null to properties[].type if nullable is true', () => {
+        const generated = generateBodyOptions({
+          requestBody: {
+            content: {
+              'application/json': {
+                schema: {
+                  properties: {
+                    redirectUri: {
+                      type: 'string',
+                      nullable: true,
+                    },
+                  },
+                },
+              },
+            },
+          },
+        });
+        expect(generated.bodySchema).toStrictEqual('{\"properties\":{\"redirectUri\":{\"type\":[\"string\",\"null\"],\"nullable\":true}}}');
+      });
+    });
   });
 });
diff --git a/packages/openapi-2-kong/src/declarative-config/plugins.ts b/packages/openapi-2-kong/src/declarative-config/plugins.ts
index 3c34193800..2042a1a004 100644
--- a/packages/openapi-2-kong/src/declarative-config/plugins.ts
+++ b/packages/openapi-2-kong/src/declarative-config/plugins.ts
@@ -85,7 +85,7 @@ const generateParameterSchema = (operation?: OA3Operation) => {
   return parameterSchemas;
 };
 
-function generateBodyOptions(operation?: OA3Operation) {
+export function generateBodyOptions(operation?: OA3Operation) {
   let bodySchema;
   let allowedContentTypes;
   const bodyContent = (operation?.requestBody as OA3RequestBody)?.content;
@@ -96,6 +96,13 @@ function generateBodyOptions(operation?: OA3Operation) {
 
     if (allowedContentTypes.includes(jsonContentType)) {
       const item = bodyContent[jsonContentType];
+      const schema = item.schema;
+      for (const key in schema.properties) {
+        // Append 'null' to property type if nullable true, see FTI-3278
+        if (schema.properties[key].nullable === true) {
+          schema.properties[key].type = [schema.properties[key].type, 'null'];
+        }
+      }
       bodySchema = JSON.stringify(item.schema);
     }
   }