Sydney man botches bank robbery

A hapless bank robber has run away empty-handed after a failed hold-up attempt in Sydney's west.

The masked man walked into the bank on Tunks Road, Seven Hills, around midday on Friday and demanded at gunpoint that a teller fill up his bag with cash.

But the teller activated the security screen and the man ran from the building empty-handed.

Forensic officers have scoured the scene and police are calling for witnesses to come forward.