The good news is the answer is “yes”, you can claim the cost of travelling to Australia against your tax if you collect rental on an Australian Property and make sure that at least part of the trip is spent inspecting the property.
Sadly, if you don’t have a property then you can not claim any of the expenses, similarly even if you do have a property you must actually visit your property in order to justify the claim.
If the primary purpose of the trip was for property related business, such as a tenant changeover, then you will be able to claim airfares in full and expenses for hotels, meals, car hire and associated costs for the number of days of property business activity.
Trips made to find or acquire a property can only offset future capital gains when the acquired property is eventually sold, but when you are already collecting rental then the trips are claimable against your annual income tax.
If the trip has dual purpose such as Christmas home, then you will be able to claim your airfares on a pro rata bases, for example if you do two days of property business on a ten day holiday, then 20% of your airfare and two days of hotel and meal costs will be able to be claimed.
You will only be able to claim expenses for the people who are on the title, so not your children.
In order to ensure you have no trouble with the Tax Office, you should keep a simple diary to confirm your activity, and keep receipts for your airfares and other expenses.
There is no maximum number of trips you can claim, as long as there is a genuine purpose to justify the trip then a claim can be made.