The software will run on the modem and monitor for malicious websites and is claimed to protect from attempts to gain access to the Wi-Fi network.
A statement from the company said the devices which could be monitored included baby monitors, security cameras, smart devices and home security devices.
Optus managing director of Marketing and Revenue, Matt Williams, said: "As part of our vision to be Australia's most loved, everyday brand, we believe it's our responsibility to assist our customers to maintain a sense of security when connecting online through our network.
Optus Wi-Fi Secure is available free to Family Internet Plan customers.
Those on other NBN plans will have to pay $5 per month in the event that they are eligible.