Hello

We are in Qld and going on a holiday before the year is out. I have a UK passport but my kids have dual so Aus and UK. This is our first time out of Aus since moving here permanently so my question is, does it matter which passport they use or MUST they exit and return on their Aus passports?
thanks

They need to use Aus passport to leave and re enter Australia. They can use their Uk passport otherwise it depends where you are going and if they need visas etc.
To enter Australia you need either a visa or an Australian passport and you can’t get a visa if you are Australian. They can’t deny you entry if you can prove you are a citizen BUT airlines are not obliged to fly you without and they are getting stricter. We were asked to show our Aus passports on flying out, even though we had our UK passports to enter Vietnam as we didn’t need a visa with that.
Last time we went to UK and Europe we travelled solely on our Aus passports.