The bellwether IHS Markit/CIPS UK Construction Total Activity Index slumped to 39.3 in March from 52.6 in February.
It was above the 50 no-change value in February for the first time since April 2019.
But Covid-19 has sparked a dramatic slump across all sectors with business optimism also falling to its lowest level since October 2008.
Construction companies also recorded intense supply chain pressures in March due to reduced capacity and shortages of stock among vendors.
The latest lengthening of lead-times among vendors was the steepest recorded since October 2014.
Lower workloads and business closures resulted in a marked reduction in staffing numbers across the construction sector during March.
The latest survey indicated the steepest pace of job shedding since September 2010.
Tim Moore, Economics Director at IHS Markit, which compiles the survey said:“March data provides an early snap-shot of the impact on UK construction output from emergency public health measures to halt the COVID-19 pandemic, with activity falling to the greatest extent since the global financial crisis.
“The closure of construction sites and lockdown measures will clearly have an even more severe impact on business activity in the coming months.
“Survey respondents widely commented on doubts about the feasibility of continuing with existing projects as well as starting new work.
“Construction supply chains instead are set to largely focus on the provision of essential activities such as infrastructure maintenance, safety-critical remedial work and support for public services in the weeks ahead.”
Duncan Brock, Group Director at the Chartered Institute of Procurement & Supply: “The battered construction sector was offered a brief respite in February with a marginal rise in output after a difficult year, but any hope of a continuation of growth was mercilessly bulldozed away in March and construction companies registered their lowest levels of optimism since October 2008.
“As measures to contain the coronavirus COVID-19 pandemic were put in place across the UK, construction sites closed and builders lost their jobs on a frightening scale as overall activity fell to an extent not seen since April 2009.
“New orders were reduced to a trickle as the scale of the disease dawned on clients and lockdown severely hindered any further progress.
“With no upturn in sight, and with the fastest level of layoffs since September 2010, the sector is stuck in quicksand and sinking further.
“Though lower commodity prices will bring some relief for those that can source a limited number of materials amidst disrupted supply chains, this will be cold comfort without sites to work in and staff available as health concerns remain.
“The brutality of this impact cannot be underestimated, and the sector has not hit rock bottom yet.”