Home loan customers are being urged to be cautious of incentives being offered by the banks to get them to sign up for mortgage deals.

ASB is offering TVs and Playstations, Kiwibank gives out Freedom Furniture gift cards and the Westpac dishes is handing over what it calls "cash bonuses".

But Karen Tatterson of the Professional Advisors Association says there's often a catch.

She says most deals require customers to extend the term of their loan.

She says pushing a loan out from 20 to 30 years could mean paying an extra $20,000 to $30,000 in interest.