Westpac says it is rolling out the new policy from this week. It means someone purchasing a $500,000 inner-city or city-fringe apartment could potentially secure finance with $75,000 deposit - down from the current $100,000 minimum.
The policy is expected to be aimed at first home buyers rather than investors and will only apply to owner-occupier apartments.
Kiwibank has also confirmed it is reviewing its apartment lending criteria in a move designed to help customers into home ownership.
"This review is well underway, however we are not yet in a position to provide any detailed information," a spokesman told the Herald.