An electrostatic discharge (ESD) protection circuit for a semiconductor integrated circuit (IC) that protects core circuitry of the IC during normal operations, and shunts ESD events during non-powered mode of the IC. The ESD protection circuitry includes a multi-fingered MOS transistor, each finger respectively adapted for coupling between an I/O pad and a first supply line of the IC. An ESD detector is coupled to the I/O pad via a first terminal, and a second terminal is adapted for coupling to a second supply line potential of the IC. A parasitic capacitance is formed between the second supply line potential of the IC and the first supply line potential. A transfer circuit is coupled to a third terminal of the ESD detector and is adapted for biasing at least one gate respectively associated with at least one finger of the multi-fingered MOS transistor.