Finance question

Can they get a deposit bond?

You have to have the collateral to be able to borrow the deposit for another property.
Say you had a property worth say $400,000 but only had a loan of $100,000 against it then you could borrow a deposit for another property. In this case you decide to add the two properties values together and get a deposit bond for the deposit as together the two properties add up to say $800,000 in Value and total loan is $500,000 then you have enough collateral to get a deposit bond for when the loan comes through and you can pay the bond back.

The main point is that you will have the funds at settlement. It is not used to keep the bank happy but rather the selling vendor happy.
have a look at this site for more insight into deposit bond requirements
http://www.depositpower.com.au/dpg/purchasers?quicktabs_4=0#quicktabs-4

A little bit confused about your situation
We are buying out in-laws on a property?
    What sort of property are you buying out from in-laws is it an investment property purchased after 2000 ?
    Why I am asking is because if they own property already purchased prior to 2000 will they be able to get FHOG ?
    or if they already own a residential property they can't get FHOG.
    Some states allow prior purchase after 2000 if investment property it varies from State to State of OZ.
My question is, can you not borrow for the deposit? The total amount of borrowing is 10% of the value of the property and they will be paying cash upon settlement for the balance.

You normally can get a line of credit loan but I think in this situation the in-laws are selling the first property and then buying another property in this situation what some people do is get a bridging loan.
see below – not recommending a lender just highlighting the product your in-laws may be after

http://www.commbank.com.au/personal/home-loans/our-borrowing-options/bridging-finance.aspx?cid=dsm
http://www.anz.com/personal/home-loans/refinancing-home-loan/bridging-finance/
http://www.xinc.net.au/home_loans/bridging_loans.html
http://www.aussie.com.au/home-loan/selling-guide/sell-or-buy-first.htm
http://www.aussielegal.com.au/forum/forum_posts~TID~6188.htm

Not sure if this will help your in-laws but sometimes the right question to ask the bank can make a big difference like asking if a bridging loan can be used.

Are you asking if it is possible for the in-laws to borrow the 10% deposit to use when purchase a property.

Generally personal loans are not available for this sort of thing.