'Remain' campaigners had warned house prices could fall if Britain left the European Union as a result of Thursday's referendum.
"We have seen a significant slowdown in the volume of transactions in the run up to the referendum and it's likely that will continue," said Andy Pyle, UK head of real estate at KPMG.
Big variations across regions and different property assets are expected.
"At its simplest, Brexit impacts commercial real estate if it reduces GDP growth, impacting long-term employment growth and future demand for office space," said analysts at UBS in a note.
KPMG said it would expect companies' appetite to enter new property leases and increase their liabilities would diminish, particularly if Britain's departure from the EU weakens London's financial district.
"Given the potential for banks to need to transfer business undertaken in London into the euro zone, we could see a particular decline in London's dominant position as Europe's leading financial and business centre, which would impact real estate demand in the City in particular."
Analysts at UBS agreed that the London office market looked particularly vulnerable because of its exposure to financial tenants. They calculated that British Land has the highest exposure to financial tenants of those stocks it covers.
The FTSE 350 Real Estate index, which had risen 8 percent in 2015, was down 15 percent on Friday. Shares in British Land plunged by nearly 20 percent while Land Securities was down around 17 percent.
Marino Valensise, head of multi asset & income at Baring Asset Management, said his firm had been cutting its exposure to UK property assets as well as British shares in general ahead of the vote and was considering reducing it further.
UBS said property stocks could yet fall another 10-20 percent.
Among housebuilders, Bovis Homes and Bellway fell 24 percent, while Redrow was down 19 percent.
Peter Andrew, deputy chairman of the Home Builders' Federation, said though it was too early to understand the implications of Brexit, there remains an acute housing shortage in Britain, which could provide a buffer.
That view was echoed by David Thomas, chief executive of Barratt Developments.
"There is a structural under-supply of quality homes in the UK, and we have a clear strategy to address this, supported by a strong balance sheet to execute our growth plans," he said.
Some estate agents said, for the time being, rental accommodation in the residential market may be favoured.
"We expect the domestic buyers to remain subdued, perhaps opting for rental accommodation, but we do we expect more interest and volumes from overseas buyers," said Charles Curran, principal, Maskells Estate Agents, pointing to the weakness in sterling attracting overseas buyers.
Real estate investment adviser London Central Portfolio (LCP), which specialises in prime central London property, said it had already received interest from Asian and Middle Eastern investors.
(Writing by Elaine Hardcastle; Editing by Adrian Croft)