An increasing number of businesses are planning to furlough staff over the next week, according to the British Chambers of Commerce (BCC).
The coronavirus job retention scheme enables employers to obtain grants to cover up to 80% of furloughed workers' wages, up to £2,500 a month.
It is initially open for three months, from 1 March 2020, although Chancellor Rishi Sunak could extend this if necessary.
Initial estimates from the Treasury predicted around 10% of employers using the state-sponsored scheme, but research from the BCC found otherwise.
Some 37% of employers plan to furlough more than 75% of their workforce in the next week, while 20% of firms intend to furlough their entire workforce.
Should that come to fruition, the total cost of the job retention scheme could soar to £40 billion by the time the initial three-month period ends on 31 May 2020.
Adam Marshall, director-general at the BCC, said:
"Many businesses face a cliff-edge scenario, either at the end of this month or over the course of the next quarter.
"We've seen a big jump in the number of firms furloughing staff, and many are starting to apply for access to loans and grants to stay afloat."