Watchman, in short, they don’t have the right to allow their toxic ‘smoke drift’ to spread to other people’s dwellings even balconies. You will have to find the part in the NSW Strata Titles Act mentioning ‘dangerous nuisance’ which second hand smoke definitely is (even if not tobacco smoke). You will have to ask your Owners Corporation and or Strata Manager in writing to order them to stop via a Notice to Comply and if they refuse or refuse to talk to you within your urgent timeframe, go straight to the NSW Office of Fair Trading using the mediation form on their web site.
Interestingly, they are also disturbing your ‘peaceful enjoyment’ under the Act. ‘Peaceful enjoyment’ isn’t just about noise so look that up in the Act too.
You’ll probably have to go in hard, Watchman, and keep your skin thick. You know what most smokers are like!