diff --git a/packages/chopsticks/src/plugins/new-block/index.ts b/packages/chopsticks/src/plugins/new-block/index.ts
index d84e0ddb..680ffe96 100644
--- a/packages/chopsticks/src/plugins/new-block/index.ts
+++ b/packages/chopsticks/src/plugins/new-block/index.ts
@@ -2,7 +2,7 @@ import { Handler, ResponseError } from '../../rpc/shared'
 import { defaultLogger } from '../../logger'
 
 export const rpc: Handler = async (context, [param]) => {
-  const { count, to, hrmp, ump, dmp, transactions } = param || {}
+  const { count, to, hrmp, ump, dmp, transactions, unsafeBlockHeight } = param || {}
   const now = context.chain.head.number
   const diff = to ? to - now : count
   const finalCount = diff > 0 ? diff : 1
@@ -16,6 +16,7 @@ export const rpc: Handler = async (context, [param]) => {
         horizontalMessages: hrmp,
         upwardMessages: ump,
         downwardMessages: dmp,
+        unsafeBlockHeight: i === 0 ? unsafeBlockHeight : undefined,
       })
       .catch((error) => {
         throw new ResponseError(1, error.toString())
diff --git a/packages/core/src/blockchain/block-builder.ts b/packages/core/src/blockchain/block-builder.ts
index 561a672d..dc9d9250 100644
--- a/packages/core/src/blockchain/block-builder.ts
+++ b/packages/core/src/blockchain/block-builder.ts
@@ -52,7 +52,7 @@ const getNewSlot = (digest: RawBabePreDigest, slotNumber: number) => {
   return digest.toJSON()
 }
 
-export const newHeader = async (head: Block) => {
+export const newHeader = async (head: Block, unsafeBlockHeight?: number) => {
   const meta = await head.meta
   const parentHeader = await head.header
 
@@ -91,7 +91,7 @@ export const newHeader = async (head: Block) => {
 
   const header = meta.registry.createType<Header>('Header', {
     parentHash: head.hash,
-    number: head.number + 1,
+    number: unsafeBlockHeight ?? head.number + 1,
     stateRoot: '0x0000000000000000000000000000000000000000000000000000000000000000',
     extrinsicsRoot: '0x0000000000000000000000000000000000000000000000000000000000000000',
     digest: {
@@ -147,17 +147,23 @@ export const buildBlock = async (
   extrinsics: HexString[],
   ump: Record<number, HexString[]>,
   onApplyExtrinsicError: (extrinsic: HexString, error: TransactionValidityError) => void,
+  unsafeBlockHeight?: number,
 ): Promise<[Block, HexString[]]> => {
   const registry = await head.registry
-  const header = await newHeader(head)
+  const header = await newHeader(head, unsafeBlockHeight)
+  const newBlockNumber = header.number.toNumber()
+
+  if (newBlockNumber < head.number) {
+    throw new Error('unsafeBlockHeight is not allowed to be less than current block number')
+  }
 
   logger.info(
     {
-      number: head.number + 1,
+      number: newBlockNumber,
       extrinsicsCount: extrinsics.length,
       umpCount: Object.keys(ump).length,
     },
-    `Try building block #${(head.number + 1).toLocaleString()}`,
+    `Try building block #${newBlockNumber.toLocaleString()}`,
   )
 
   let layer: StorageLayer | undefined
diff --git a/packages/core/src/blockchain/txpool.ts b/packages/core/src/blockchain/txpool.ts
index d0bb3924..e273dfaf 100644
--- a/packages/core/src/blockchain/txpool.ts
+++ b/packages/core/src/blockchain/txpool.ts
@@ -34,6 +34,7 @@ export interface BuildBlockParams {
   upwardMessages: Record<number, HexString[]>
   horizontalMessages: Record<number, HorizontalMessage[]>
   transactions: HexString[]
+  unsafeBlockHeight?: number
 }
 
 export class TxPool {
@@ -171,6 +172,7 @@ export class TxPool {
     const upwardMessages = params?.upwardMessages || { ...this.#ump }
     const downwardMessages = params?.downwardMessages || this.#dmp.splice(0)
     const horizontalMessages = params?.horizontalMessages || { ...this.#hrmp }
+    const unsafeBlockHeight = params?.unsafeBlockHeight
     if (!params?.upwardMessages) {
       for (const id of Object.keys(this.#ump)) {
         delete this.#ump[id]
@@ -186,6 +188,7 @@ export class TxPool {
       upwardMessages,
       downwardMessages,
       horizontalMessages,
+      unsafeBlockHeight,
     })
   }
 
@@ -231,6 +234,7 @@ export class TxPool {
       (extrinsic, error) => {
         this.event.emit(APPLY_EXTRINSIC_ERROR, [extrinsic, error])
       },
+      params.unsafeBlockHeight,
     )
     for (const extrinsic of pendingExtrinsics) {
       this.#pool.push({ extrinsic, signer: await this.#getSigner(extrinsic) })
diff --git a/packages/e2e/src/build-block.test.ts b/packages/e2e/src/build-block.test.ts
index bfc4e886..1f1c631e 100644
--- a/packages/e2e/src/build-block.test.ts
+++ b/packages/e2e/src/build-block.test.ts
@@ -40,4 +40,14 @@ describe.each([
     expect(chain.head.number).eq(blockNumber + 2)
     await teardown()
   })
+
+  it.runIf(process.env.CI)('build block using unsafeBlockHeight', async () => {
+    const { chain, ws, teardown } = await setup()
+    storage && (await ws.send('dev_setStorage', [storage]))
+    const blockNumber = chain.head.number
+    const unsafeBlockHeight = blockNumber + 100
+    await ws.send('dev_newBlock', [{ count: 2, unsafeBlockHeight }])
+    expect(chain.head.number).eq(unsafeBlockHeight + 1)
+    await teardown()
+  })
 })