BEIJING—Cybersecurity proposals by China have U.S. businesses worried that the draft regulations represent additional barriers to the Chinese market, a concern that could complicate U.S.-China trade talks.

The new rules and standards, floated over the past two months with little fanfare, flesh out an existing cybersecurity law that Washington and many foreign businesses already consider draconian. Some would forbid certain data from leaving China or at least slow the process of dispatching data, which would increase uncertainties and costs for business. Tough rules for procuring equipment could also place foreign products at a disadvantage.

If enacted, the measures are likely to hit a swath of American companies, including such tech manufacturers as Cisco Systems Inc., International Business Machines Corp. , Juniper Networks Inc. and Dell Technologies Inc. Providers of financial services and the automotive sector also could be affected.

U.S. businesses and trade groups say some of the proposals are too vague and give Chinese officials leeway on enforcement. The Cybersecurity Administration of China and the Ministry of Public Security, which are involved in the various drafts, didn’t respond to requests for comment.

The rules reflect multiple factors shaping China’s cybersecurity landscape, including growing consumer awareness over data privacy and a recent global trend of establishing new privacy rules, experts say.