The one-year rate has been dropped from 5.25% to 4.89%, the three-year rate from 5.9% to 5.35% and the five-year rate from 5.99% to 5.75%.
The rates are the cheapest carded rates of all the major banks but Westpac said they were being reviewed weekly.
For three-year terms, ANZ has 5.90 per cent, ASB is advertising 5.75 per cent and Kiwibank has 5.65 per cent.
The median five-year rate among the major banks is 6.5%.
Borrowers need 20% deposit and a minimum loan of $100,000 to take up Westpac's latest offer.
