Most electric meters are attached to external walls of the house. Houses usually have them installed near the front door, or the side of the house. If you live in an apartment, unit, or townhouse, you can usually find it grouped with the meters of other residents in one central location.
Here are some pictures of the different Australian electricity meters for reference.
If you live in NSW, the gas meter could be located under the kitchen sink, so check there first. If not, your gas meter is usually located directly next to your house, mostly on the front left or right of your house. If you live in a unit, apartment or townhouse, all of the meters for each residence will likely be in a central location. Common locations for gas meters in multi-dwelling buildings are basements and car parks.
Here are some pictures of Australian gas meters for reference.
In case you can’t find it in the said locations, you may contact your landlord, building manager, or realty property owner.