I'm hoping to use aluminium pool fencing (vertical poles as sold by Bunnings) for deck railing (approx 2 metres off the ground) with a horizontal timber railing above it.
Can you please confirm this material is legal to use for this.
We can't really comment without more info about the product you're talking about or how you plan to use it - and we're not the right people to tell you one way or another about that anyway...
For what it's worth, the requirement in the building code is for balustrades and handrails to be constructed so that they're able to resist the forces that are reasonably expected to be placed upon them (which includes people leaning or falling on them, and strong winds) - that's up to a specific amount of force in different given directions, both as point loads and evenly distributed loads.
Whether or not those poles fit the bill will probably depend on both how the poles are constructed, and how they're incorporated and attached.
They'll need to satisfy both the structural loading requirements specified in AS/NZS 1170 - Structural design actions, and the balustrade / handrail design requirements in the Building Code of Australia Parts 3.9.1 and 3.9.2 (among other things).
Here's a little more information about what's required in the construction of balustrades and handrails.
We know it's a long, complicated answer, but barriers really aren't something you want to take chances with. We'd strongly recommend you talk to your local council's building department, an engineer or a balustrade manufacturer about what's safe and compliant.
Hope this helps,
The BUILD team.