Amazon's grocery delivery is hit or miss for many shoppers. As demand continues to surge, Amazon announced that new customers of Amazon Fresh and Whole Foods Market will need to sign up for an invitation before they can shop at these services.

"We are asking new Amazon Fresh and Whole Foods Market customers to sign up for an invitation to take advantage of temporary online grocery delivery and pickup," Amazon wrote in a blog post." We are increasing capacity weekly and will be inviting new customers to shop weekly," Amazon wrote in a blog post. The news comes weeks after rumors circulated that Amazon Prime Day might be postponed to August.

In the same blog post, Amazon also said it will adjust store hours at some Whole Foods Markets so that stores can focus solely on fulfilling Amazon grocery orders.

Here in New York City, a local Whole Foods Market in Bryant Park sent the following email:

"Effective April 15, the Whole Foods Market store in Bryant Park will focus on Prime grocery delivery and fulfilling more orders, The store will be temporarily closed. We apologize for any inconvenience this may cause, as we will do our best to serve our customers responsibly during this critical time."

Amazon grocery delivery is experiencing an unprecedented surge in demand. Last month, Amazon temporarily shut down Prime Pantry for a week, after which Prime Pantry went back online. However, more than a week later, many shoppers are still experiencing delays in service.

On March 16, Amazon announced that it would hire an additional 100,000 workers to meet demand. It also said it would invest more than $350 million to support its employees and partners during the COVID-19 crisis. Today, the online giant announced that it will hire an additional 75,000 people on top of the 100,000 it already employs.