The latest figures from the Council of Mortgage Lenders put the dramatic fall down to the lending surge in March driven by the end of the stamp duty holiday.
First-time buyer purchases for properties over £250,000 not eligible for the exemption in any case fell by only 5%.
In total 12,600 loans were advanced to first-time buyers, down by 48% compared to March and 12% compared to April 2011.
By value first-time buyers borrowed £1.5bn, down 52% compared to March and 12% compared to April last year.
The change in the mix of properties bought had knock-on effects on first-time buyer loan characteristics.
The average loan amount fell from £117,000 in March to £98,000 in April and first-time buyers typically borrowed 3.12 times their income, down from 3.34 in March.
These changes are almost wholly because of the trend in April towards cheaper properties rather than a real improvement in affordability for first-time buyers, said the CML.
Lending to home movers also fell with 23,400 loans worth £3.8bn taken out in April, down by 15% (14% by value) compared to March but an increase of 3% (by volume and value) compared to April 2011.
Total house purchase lending in April fell from 51,600 loans worth £7.4bn in March to 36,000 worth £5.3bn in April.
Remortgaging also saw a fall with £3.1bn advanced, down 14% compared with March and the lowest monthly total since December 2010.
Nearly all first-time buyers currently take out repayment mortgages - 98% in April, unchanged from March.
The proportion of home movers and those remortgaging doing so also continues to increase with around 85% of home movers and 82% of remortgagors taking out full capital repayment mortgages.
Reflecting the fact that repayment mortgages are now taken out by the vast majority, CML monthly data will now show the total proportion of income spent on capital and interest payments by those choosing this method, as well as the longstanding affordability measure of the proportion of income spent on interest alone.
In April, first-time buyers spent 19.1% of their income on both payments (compared with 12.5% on interest alone), down from 19.8% in March (13.1% on interest alone).
Paul Smee, director general of CML, said: “April's figures show the expected effect of the end of the stamp duty concession on UK mortgage lending. Given the economic uncertainty, any significant pick up in lending in the coming months seems unlikely.
"However, our recent research highlights that over 80% of people still aspire eventually to own their own homes, and long term demand clearly still exists."
