The nonprofit group that manages the Internet’s address system needs to take steps to ease corporate concerns over a program to add hundreds of top-level domains beyond .com and .net, the U.S. Commerce Department said.

Once the application period for Web suffixes ends, the Internet Corporation for Assigned Names and Numbers should assess the need to phase in the introduction of domains, Lawrence Strickling, Assistant Secretary of Commerce, wrote in a letter Jan. 3 to Icann Chairman Stephen Crocker.

During meetings with business representatives in recent weeks, the Commerce Department has “learned that there is tremendous concern about specifics of the program that may lead to a number of unintended and unforeseen consequences and could jeopardize its success,” Strickling wrote.

General Electric Co., Johnson & Johnson and Coca-Cola Co. are among more than 40 companies that have joined with the Association of National Advertisers to oppose the expansion, saying it will increase costs for companies, confuse customers and create new risks of Internet fraud.

Icann, operating under a Commerce Department contract, approved a plan in June to expand the number of top-level domains beyond .com, .net and .org to spur online innovation. The group was expected to start accepting applications Jan. 12 for Web suffixes including company and brand names, cities and words such as .book. Applications will cost $185,000 for each domain.

In the Jan. 3 letter, Strickling also urged Icann to take steps to “minimize the perceived need” for trademark owners to defensively register new top-level domains that they have no interest in operating, and improve awareness of the “purpose and scope” of the program.