In Queensland, the release of balloons into the environment is considered littering under the Waste Reduction and Recycling Act 2011—whether released deliberately or by accident. While a person may have the permission of the occupier of a place to release a balloon, once the balloon leaves that place it becomes litter.
Under the Protection of the Environment Operations Act 1997 No 156 (section 146E) It is illegal to release 20 or more gas-inflated balloons at or about the same time. The balloons should not have any attachments. On-the-spot fines can be given and penalties are much higher if over 100 balloons are released