The average price of a £3m home in areas such as Knightsbridge and Belgravia rose 9.6% in the second quarter from a year earlier, according to the company. The quarterly gain was 3.4%.
“Overseas demand has been much stronger than we expected,” Lucian Cook, a researcher at Savills, told Bloomberg.
“The big unknown is what happens in Greece – will it be a catalyst for more demand because of the outlook for the euro region?”
Buyers based outside the UK have been competing over a below-average number of properties for sale in central London as they seek a haven for their wealth amid political and economic uncertainty at home.
The pound’s 25% slide against a basket of other currencies since the housing market peak in late 2007 has made London property more attractive.
In November, Savills forecast a 1% decline for luxury apartments and houses in central London, predicted a pick-up in the number of properties for sale and said deteriorating economic conditions would deter British buyers.
Overseas buyers accounted for 72% of prime central London property purchases in the first quarter, compared with 60% three years earlier, according to Hamptons International.
Savills predicts average values of prime residential real estate outside London will fall by 3% this year. In November it predicted a 1% drop.