I think the landlord will have a hard time to claim this
In NSW a landlord can only pass on utility costs if they are metered.
For example on a water bill the landlord can pass on the water usage and waste water charges, but not the supply charge
I think the strata manager is also doing it wrong. For centralised amentities, the “bill” is paid thriough levies , that are paid by all lot owners. You cant just divide up a bill and separately pass on to lot owners. Thats what ythe administrative fund is for
Thirdly, is its not in your rental agreement, its not a charge that can be passed on by the landlord.
Push back. You wont have any argument from NCAT