The companies will meet European Commission officials on Monday in a meeting called by the EU competition authority, indicating worries about China's largest-ever foreign investment and the impact on consumers and rivals in Europe.

ChemChina (China National Chemicals Corp) and Syngenta hope to remove concerns but are willing to propose concessions if they cannot convince the regulator in order to get the deal approved during the Commission's preliminary review, the person said, declining to provide details.

Commission spokesman Ricardo Cardoso declined to comment. Such a proposal would trigger a 10-working day extension to the Commission's deadline of Oct. 28.

The EU enforcer can demand more concessions if it feels the proposal is not sufficient or it can open a full-scale investigation that can take as long as five months.

(Reporting by Foo Yun Chee; editing by Alastair Macdonald and Susan Thomas)