High LTV approvals – typically for first-time buyers – fell by 10.5% from February to March.
The same trend was mirrored across the whole market, as mortgage demand dropped by 2.4% in March for all borrower types.
Richard Sexton, director of e.surv chartered surveyors, said: “Smaller deposit borrowers, typically first-time buyers, are among the most cautious borrowers.
“Picture yourself buying a home for the first time – investing a carefully husbanded nest-egg into a property you want to enjoy and likely resell at some point in the future.
“It’s understandable that they might want to wait for the dust to settle after the election before they make the leap.”
The number of approvals year-on-year mortgage fell by 10% to March 2015 as there were 60,280 loans approved, down from 66,970 in March 2014.
But the trend is still towards growth, as on a quarterly basis there were 182,747 house purchase approvals in the first quarter of 2015, 2.3% more than the 178,579 recorded in the fourth quarter of 2014.
Sexton added: “This is an unwelcome though not unexpected setback. You can lead a horse to water, but you can’t make it drink.”
While high LTV lending remains strongest up North as a proportion it fell in the Northwest (24% to 21%) and also in Northern Ireland (27% to 22%) from February to March.
