British house prices increased by 5.7 percent in the year to May 2015, up from 5.5 percent in the year to April 2015, according to official data released Tuesday.

On a seasonally-adjusted basis, average house prices increased by 0.9 percent between April and May 2015, said the Office for National Statistics (ONS).

The average mix-adjusted house price in May 2015 was 274,000 pounds (428,164 U.S. dollars) and London continued to be the region with the highest average house price at 503,000 pounds, said ONS.

"The UK housing market showed some signs of picking up in May 2015," said ONS's monthly report.

"May's stronger growth figures suggest a pick-up in housing market activity, possibly driven by a continuing mismatch between supply and demand," it added.