Gross mortgage lending fell six per cent year-on-year in August to £13.3bn, the Council of Mortgage Lenders has said.
That was the lowest August total since 2000 and represented a drop of 14 per cent from July.
The figures chimes with other surveys in showing a cooling in the housing market following a sharp recovery in the second half of 2009.
Figures from the Bank of England on Monday showed major lenders approved just 45,000 mortgages in August, the lowest level in more than a year.
"We face the prospect of a difficult second half of the year," said CML chief economist Bob Pannell. "However, the Bank of England is likely to keep interest rates at record lows for longer to support the economy. This will continue to alleviate payment pressures for many borrowers."