London homeowners are showing a "marked reluctance" to put their property up for sale, deterred by uncertainty caused by the looming Brexit process and an increase in tax, according to Rightmove, a British property website.

While the average asking price of a property in the British capital rose 1.4 percent in January to 624,953 pounds ($759,000), fewer Londoners put their properties up sale. New listings slid 14 percent from a year earlier, the website operator said on Monday.

"Last year saw a rush of owners trying to exit at what they perceived as the top of the market, though in truth those in inner London were already a year too late," said Rightmove Director Miles Shipside. "Owners now seem well aware of the more challenging conditions, with the high stamp-duty costs and Brexit uncertainty perhaps making them hold back from trying to sell."

London's underperformance was a theme of 2016, with Britain's vote to leave the European Union as well tax changes in the early part of the year weighing on the market. Rightmove said last month that prices in prime London property could decline 5 percent this year.

Across the United Kingdom, asking prices rose 0.4 percent in January from December, and climbed an annual 3.2 percent to an average 300,245 pounds, according to Monday's report.

In a separate release, LSL Property Services and Acadata said annual UK house-price inflation slowed to 3.1 percent last month.

Transactions declined 3.9 percent last year from the previous year. The report also reflected slowing growth in London, which trailed the other regions of England and Wales with home-price growth of 0.2 percent last year due to a slump in prime property.