You can purchase a house for as little as 5% deposit but this depends on the policy of the lender, your financial capability and status. Having said thaT, you will need more than 5% in actual cash because there are other costs involved when purchasing a house such as application fees, LMI,solicitor/conveyancor fees, inspection fee, valuation fee etc. at the minimum, one must prepare at least 8% of the purchase price.
Some will say, save up to 20% deposit to avoid LMI but you must assess if it is worth to avoid LMI (a couple of thousand $$ depends on purchase price) and wait years and years until you have saved enough deposit but then by that time the property prices have already gone up. You can purchase a house with low deposit, pay LMI and actually earn $$$ if equity on your house goes up. Most of the time, paying LMI makes much more sense rather than waiting to save up 20%. Sometimes lenders will also have promotions where they waive LMI (subject to certain criteria) and some professions such as doctors, lawyers, accountants, etc can be eligible for LMI waiver.