Hi Pez and Sarn,
standard loan term in Oz is 30 years. Lenders restricting the loan term is not usually applicable unless the youngest applicant is aged over 55. So, looks ok for you there. If both applicants aged over 55 then they may require evidence of post retirement income or superannuation/pension payout to enable the debt to be paid out on retirement.

Note: as an aside, I would generally discourage anyone from structuring a loan over a term less than the maximum the lender will give you. If you want to pay off the debt quicker, say 15 years, then just make extra payments rather than commit yourself to a shorter repayment term. This give you the ability to reduce your repayments if you need to (if your income drops dramatically for example), and the extra payments can often be "withdrawn" (called redraw) in case you need the money too.

Loan of $150,000 x 4.99% = $804 per month, $402, per f/n or $201 per week currently. Allow for rates going back up to say 6.99% and repayments = $996 per month, $498 p/f, $249 per week.

Currently, the Government gives first home buyers $18,000 to help them buy an established home ($25,000 if newly constructed). However, they take back around $13,000 in government fees and charges! So you would have about $5,000 of this left over. Allow about another $1,500 say for lender fees, legal (conveyancing) expenses and adjusted council rates etc, and you have $3,500 net towards the purchase.

So, with cash of $150,000 and a loan of $150,000 you could buy a property around $300,000.

Hope this helps. Feel welcome to PM me anytime if you want more detail concerning your specific circumstances.
Kind regards