Mortgage experts believe banks will increasingly resort to handing out free cash and other add-on incentives to preserve their lending volumes over the next 12 months.National Australia Bank is the latest big lender promising to throw money at prospective home borrowers as demand for credit slides in the wake of tightened lending standards and the property market price correction.NAB announced on Monday that it had begun to pay A$1,250 to borrowers who also sign up to bundled banking deals with the bank when they take out a mortgage.Under the offer, which applies to home loans applications above $250,000 up to 2 December, the bank will pay the cash bonus if the borrower also opens a transaction account.The bank said in a notification to mortgage brokers that the cash bonus was part of a concerted marketing campaign aimed at winning new mortgage business.Mortgages will be the focus of NAB's television advertising until the end of the year, after the launch of the "Home Loans - Alive with possibilities" campaign that began going to air during AFL telecasts over the weekend.NAB appears to have abandoned rewards points in mortgage marketing following a sustained effort over the last 12 months to attract new borrowers through loyalty scheme incentives. The move indicates that a similar cash incentive marketed by NAB subsidiary Ubank earlier this year may have achieved greater cut through than the parent's rewards points offers.Ubank has been offering borrowers a $1000 cash bonus for most of this year if they also open a savings account.Westpac subsidiary St George Bank recently ditched rewards points in favour of cash by offering $1500 on mortgage refinancings.The St George offer also requires borrowers to link their loan to one of its transaction accounts.Mozo data manager Peter Marshall said he expected more lenders to switch to cash incentives in coming months."The tightening of lending standards has made it more difficult for lenders to replenish their home loan books," he said."I suspect banks will be rejecting more borrowers going forward, so they need to find more ways to get them in the door."Most of the banks are not in a position to reduce rates as funding pressure grows, but cash bonuses might be the next best incentive."Marshall believes the major banks are poised to increase standard variable rates in the next few months because of the rising cost of funding in wholesale markets."I still think we will see the big banks move," he said."Each of the majors have made it clear they are facing headwinds."