The society is now lending up to 75% LTV on buy-to-let new builds.
Principality Building Society has increased its new build maximum loan-to-value from 85% to 90% loan-to-value on residential mortgages.
The society said it made the change in response to an increase in new build houses and flats being built across the UK.
Shaun Middleton, head of regulatory sales at Principality, said: “The UK’s new build market is showing positive signs of growth, with a much healthier outlook in the long run for those hoping to get on the property ladder.
“But we understand that many first time buyers across the country have smaller deposits so are looking for mortgage products to reflect that.
“Principality is expanding its mortgage lending offers on new build properties to give more choice to buyers for their needs and, importantly, help the new build market continue to prosper.”