Welcome to Workshop. We're pleased to have you as our latest member. We hope you get lots of helpful information and inspiration for your projects from our community. Please let me know if you need a hand getting the most from the site.
I would recommend you start by taking a look at the pet doors category on the Bunnings website. There is a number of lockable options. Hopefully community members will also be able to recommend models based on their experiences.
All the best,
The manufacturer may of discontinued them, I know SA still has some.
Someone has done a review albeit a bit biased as they also sell pet doors but it still doesn't look like a product I would buy.