Not against PAYG earnings they don't. Any Tax breaks should be isolated to the assets or group of assets. That would be more likely to ensure investment decisions made on the asset rather than a government backed winner.
In some cases sole traders and partnerships can claim a loss against other income. From the ATO
If you're a sole trader or a partner in a partnership, you may be able to claim business losses by offsetting them against other income - for example, income you earn from salary or wages
Also once the property becomes positive the investor has to add the profit to the payg income and effectively pay tax in the highest bracket the wages put them in, unlike companies that get the very favourable reduced tax rate.
Again if the tax breaks were so good the super rich would own entire suburbs. They dont.