I took one of those aluminium beach chairs (you know the low ones where you sit with your legs stretched out in front) on the GVBR, which weighed in at around 1.3kg. (bought at a local camping shop)
Hubby's chair, which was an aluminium director's chair style with arms, came in at around 1.8kg.(bought at Bunnings)
You can do a lot better than 3kg for a chair, but you do need to look around a little bit and make sure it has an aluminium frame rather than a steel one.