Mortgage searches fell 15% year-on-year to around 1.59 million in May, data from Twenty7tec shows.
This was also 7% lower than the April figure.
Home searches were 16% lower than last year and 7% lower month-on-month at 1.34 million.
The number of renewed mortgage applications for homes was 21% lower year on year, namely 563,124.
Searches from people looking to buy a home fell 11% year on year to 626,029.
Within this, the number of searches for new buyers fell by 14% to 152,355.
Buy-to-let searches fell 13% year-on-year and 9% month-on-month to 249,403 in May.
Within this, searches for buy-to-let mortgages fell even more sharply, by 22% compared to last year.
Searches for refinancing a rental mortgage fell by 8% year-on-year.
Despite softer search activity, availability of mortgage products rose in May after falling in April, Twenty7tec found.
The criteria-based search data also demonstrates the complexity of the cases advisors encounter.
Questions about a joint borrower (JBSP) returned to the top of the rankings, alongside searches relating to visa applicants, non-UK nationals, adverse credit and self-employed borrowers.
Nathan Reilly, Chief Customer Officer of Twenty7tec, said: “Following increased activity earlier this year, May data suggests the market has entered a more cautious phase.
“One of the most interesting aspects of this month’s report is the continued demand for complex credit criteria.
“JBSP searches returned to the top of the rankings, alongside searches related to visas, foreign nationals, adverse credit applications and self-employment.
“These remain some of the most common questions that advisors seek answers to, reinforcing the increasingly specialized nature of mortgage advice with a human touch.
“The May figures do not necessarily indicate a market in decline, but rather one that continues to adjust following increased activity earlier this year.”