Housebuilders Bellway and Persimmon are shutting construction sites despite being allowed to stay open amid the lockdown to help protect workers from coronavirus.
Bellway said it was closing its 200 building sites across the country by the end of Friday, with site managers only allowed onto developments to maintain security or to hand over keys to buyers.
Persimmon confirmed it is also starting an “orderly shutdown” of its construction sites.
It said it would continue with essential work only, making partly-built homes safe, where otherwise customers could be left in a vulnerable position.
Bellway has already shut its sales offices and Persimmon is closing its sales network from Thursday, offering telephone and online-only customer support.
Bellway chief executive Jason Honeyman said the decision to shut its construction sites in spite of being exempt from the government-imposed lockdown came as a result of fears for worker safety.
He said: “We weren’t convinced we could police the social distancing or keep workers two metres apart at sites.
“There’s always some people who ignore it.”
He added that the group was also unable to get materials as builders’ merchants are closed and there are no deliveries.
It comes as pressure is mounting on Prime Minister Boris Johnson to order that all non-essential construction work is halted amid worries that workers travelling to sites will hamper efforts to stop the spread of coronavirus.
In its half-year results, Bellway also cautioned it expects buyer demand to “almost cliff edge” as the UK locks down.
The group said sales have plunged by around 40% this week as strict new social distancing measures came into effect with cancellation rates also more than doubling to around 30%.
Mr Honeyman said: “I would expect it [sales declines] to continue beyond that and almost cliff edge.”
Persimmon also warned it was “preparing for a significant delay in the timing of legal completions, a rise in cancellation rates and a material slowdown in new sales”.
Interim figures from Bellway showed a 7% fall in pre-tax profit to £291.8m for the six months to January 31.
Revenues rose 3.6% to £1.54bn, but average sales prices fell slightly to £286,570, from £293,832 a year ago.