Japan is finalizing a plan that will tighten scrutiny of foreign investment in 12 key sectors, four government sources with knowledge of the matter have said.

The sectors would include industries like defense, nuclear power, aerospace, utilities, gas, cyber security and telecommunications, two of the sources said.

Under the plan, foreign investors purchasing a stake of 1 percent or more in certain companies in Japan will be subject to prescreening, against 10 percent now.