The number of workers on UK payrolls dived more than 600,000 between March and May, official figures suggest.
The Office for National Statistics (ONS) said the number of job vacancies in May had also fallen to a record low.
The figures reflect the impact of around six weeks of lockdown in the UK, in which almost nine million workers have been furloughed.
But economists say the full impact on employment will not be felt until wage support schemes end in October.
Jonathan Athow, deputy national statistician for economic statistics at the ONS, said: “The slowdown in the economy is now visibly hitting the labour market, especially in terms of hours worked.
“Early indicators for May show that the number of employees on payrolls were down over 600,000 compared with March.”
He added that the number of people claiming work related benefits had climbed again, although “not all of these people are necessarily unemployed”.
Overall, the UK unemployment rate held steady at 3.9% in the three months to April.
However, the Office for National Statistics said the total number of weekly hours worked in period had hit a record low as millions of workers were furloughed.
It comes after large parts of the economy were shut to fight coronavirus.
Economists believe the full impact on employment will not be felt until wage support schemes end in October.
Capital Economics economist Ruth Gregory warned bigger unemployment rises were on their way.
“It was abundantly clear in every other indicator that the labour market has weakened dramatically.
“Despite the apparent stability of the actual unemployment rate, the labour market data were still pretty awful. And some of this will surely start to filter through into the actual unemployment figures as the government’s job furlough scheme is wound down from August.”