When a few years ago lenders were threatened with newcomers to their market charging lower interest, they invented the 'basic variable rate' home loan.  This loan matched - or beat - the newcomers interest rate cuts.  But the lenders didn't want all their high profit customers refinancing into cheaper home loans. 

So they restricted flexibility on them.  On some you weren't able to repay additional amounts to reduce your home loan balance.  On others, you could do this, but you couldn't get access to a redraw.  A redraw facility enables you to re-borrow money which you have paid into your account in addition to your normal repayments. 

redraw facilities are now available on most basic variable rate home loans, though you will pay a fee to use them.  Sometimes the fee is $15, but the usual fee is around $50.  Indeed, if a redraw is not available on a home loan, it is a fair chance that the lender is not very serious about the loan.  Some lenders have very inflexible home loans on their books precisely in order to attract borrowers after the lowest rate who are scanning lists of lenders' interest rates.  After a borrower has all the restrictions explained to them they usually won't want to go ahead, but they will have their foot in the door so they can be sold a more expensive home loan.

The other, more sophisticated way of achieving what a redraw enables you to do is an offset account - though these are generally only available at basic variable interest rates to those qualifying for professional packages.