ATO have a checklist they go through to determine residency, and if you maintain a home in Australia and your family live there, you are on very shaky ground claiming to be non resident. A few Cathay pilots came short on this one, trying to quietly ease into an Australian base after a few years in Hong Kong. Spend less than six months at home, use a mates address in HKG and hope the ATO don't notice.
Best bet is to find a GOOD accountant (not one sitting at a desk in a shopping centre doing $65 tax returns), get him to set things up for you to avoid any expensive mistakes.
Note that if you are non resident you are taxed 29% from the first $ on all Australian income, ie renting your house out.
If you can get out of the Aussie tax system it's well worth a few sacrifices. Over here I worked six months of the tax year and only paid $3100 on a reasonable F/O salary. Did my own tax return in about 20 minutes, tax form is only two small pages. Even as a Captain I won't make the top rate of 20% as that only kicks in above AU$250 000
