The decision comes in response to uncertainty caused by the UK’s decision to leave the EU, the bank said.
The vote on 23 June caused global market turmoil and pushed the pound to 31-year lows. The Singapore dollar has gained about 10% since the referendum.
Singaporeans were the top Asian buyers of UK commercial property in 2015, according to consultancy Knight Frank.
UOB told the BBC in a statement: “We will temporarily stop receiving foreign property loan applications for London properties.”
“As the aftermath of the UK referendum is still unfolding and given the uncertainties, we need to ensure our customers are cautious with their London property investments.”
Singapore’s biggest lender, DBS, is continuing to provide financing, but is advising its customers to be cautious.
“For customers interested in buying properties in London, we would advise them to assess the situation carefully,” DBS executive director of secured lending, Tok Geok Peng, told the BBC.
“With foreign exchange risks, even if the value of the overseas property rises, any gains will be eroded if the country’s currency depreciates against the Singapore dollar,” Mr Tok explained.
Singapore’s other big lender, OCBC bank, said that it had not made any changes to its advisory policy.
Head of consumer secured lending Phang Lah Hwa said that OCBC was still making financing available for London properties and was “monitoring the situation closely”.