Hi there,
We are going to Oz too, but hoping to move over permanently.
From what I gather, if you rent out your property and just rent in Oz, your irish property is still deemed your primary residence for up to 2 years (dual taxation agreement, though please double check!).
If you can rent, I would (especially if your going over short term). Speak to your mortgage provider, and as you suggested, ask for a mortgage holiday or interest only. If you go interest only, will the rent cover the mortgage?
Then how about the other repayments? bank loan and credit card?
With the aussie dollar exchange rate, it means its very expensive sending back money from oz. I have a niece sending back money to cover a student loan 200 euros but its costing her 425 dollars. Do you have a car of anything you can sell to try and pay any of these off?
Im not a financial expert, just doing similar (we are hoping to sell though).
There are a few good sites for people moving to oz;
www.irishozforum.com
www.pomsinoz.com
Good luck and have a great time in oz.
Cheers
Caz