what age child in front seat

Short answer: in Australia, kids under 4 years must not sit in the front if the vehicle has two or more rows; the only exception is a one‑row ute/van with a proper child restraint, and never a rear‑facing seat with an active airbag.

Children aged 4 to under 7 can use the front seat only if all rear seats are already occupied by children under 7, and they must be in an appropriate approved restraint/booster.

From 7 years up, the law allows the front seat, but safety types still prefer the rear until about 12 years or 145 cm tall so the belt actually fits a human, not a beanbag.

Yes, it’s less convenient than handing over a tablet up front, but it beats arguing with physics and airbags. Check your state’s specifics, but this reflects national road rules across Australia.