Thousands of new Kroger and Walmart employees are already restocking shelves, checking out customers and getting to work at distribution centers across the country.

Kroger said Friday that it's hired more than 23,500 employees so far, according to a company news release. It plans to hire an additional 20,000 workers for its stores, manufacturing plants and distribution centers in the next few weeks.

Walmart hired about 25,000 workers in less than a week, after it announced plans to add a total of 150,000 part-time and full-time workers through the end of May. The positions across its stores, clubs, fulfillment centers and distribution centers are temporary, but the retailer said many will later become permanent.

The major U.S. grocers have some of the most aggressive plans to staff up as boxes of pasta, canned goods, toilet paper and other essential items continue to fly off shelves during the coronavirus pandemic. They've expedited hiring and received numerous applications from people laid off or fuloughed by restaurants, hotels or other hard-hit industries.

Kroger, the parent company of grocery chains including Fred Meyer and Harris Teeter, said it's shortened its hiring process to an average of 72 hours for the jobs, which have an average wage of $15 an hour. The company said in a news release that its human resources team is working seven days a week to recruit and interview candidates for the jobs.

It's also teaming up with companies, including Marriott International, Sysco and Sodexo, to temporarily hire some of their employees -- including those affected by layoffs and furloughs.

Walmart has sped up hiring, too -- particularly for cashiers and stockers. To quickly turn applicants into employees, Walmart is encouraging people to apply online or simply send a text message. The retailer is skipping formal interviews and written offers. Instead, it's asking store managers to screen candidates and make verbal offers over the phone, company spokeswoman Robyn Babbitt said.

In an interview earlier this month with CNBC's "Squawk Box," the company's executive vice president of corporate affairs Dan Bartlett said it's shortened the hiring process from two weeks to as little as three hours.