Tony Reardon, who heads the National Treasury Employees Union, said separately that the “initial wave” will include about 10,000 employees at 10 locations who will be “opening taxpayer correspondence, handling tax documents, taking taxpayer telephone calls and performing other functions related to the filing season.”

The IRS shuttered all of its processing and taxpayer assistance centers in recent weeks to shield its workforce from exposure to the coronavirus, and thousands of its employees have been teleworking. But it is now scrambling to get economic stimulus payments to millions of Americans and to implement other key elements of the economic rescue package enacted last month.

The agency is asking for volunteers and offering incentive pay, Reardon said in a statement, but will order employees back if there are not enough volunteers.