Just days before China's new cybersecurity law goes into force, foreign companies are grappling with rules that could tighten what is already one of the world's most restricted technology regimes.

Recent changes to the language of the law ahead of its June 1 implementation, such as a broader definition of those affected, could drag in a wider array of services and products. While industry groups are lobbying for a delay, the government is moving ahead.

China is bringing in a raft of new measures, giving the government unprecedented access to foreign companies' technology, as it bolsters control of the collection and movement of data. Forcing companies to store information within the mainland has already led some to tap cloud computing providers with more local server capacity, a potential boon to homegrown Alibaba Group Holding and Tencent Holdings at the expense of Amazon.com and Microsoft.