Beijing is planning to create a new Silicon Valley equivalent in southern China.
A "Greater Bay Area" designed to rival California's tech centre would cover 21,815 square miles and have a population of more than 67 million people.
The region would include Hong Kong and Macau, as well as part of mainland China.
Officials approved a plan at the weekend and details are due to be unveiled in February, according to local reports.
The plan means mainland China could capitalise on the international reputation of Hong Kong and Macau for tourism, finance and trade.
Shenzhen is seen as China's tech hub, the headquarters of giants such as Huawei.
The area's four major cities, Hong Kong, Macau, Guangzhou and Shenzhen, would have different roles in the region.
Zhang Xiaoming, an official for Hong Kong and Macau, told a state broadcaster on Saturday that the blueprint had been completed.
"Under the new circumstances, Hong Kong and Macau still have their unique position and advantages that cannot be replaced," he said.
Guangzhou will function as a central city, while Shenzhen will take on a role as a special economic region and an innovative city, he added.
He also revealed that almost 20,000 people from Macau had applied for a new residency permit, which would allow them to access social and public services in mainland China, since it became available on September 1.
A US$15 billion ($22.1b) bridge connecting Hong Kong and Macau opened last year, and bullet trains will also connect Shenzhen and Hong Kong.