The Woodland Hills and Tarzana chambers of commerce will join forces in a merger that will take effect Jan. 1.

The move is an effort to exert more influence over local policies to give members a stronger voice in economic, political and government advocacy.

The Woodland Hills-Tarzana Chamber of Commerce will have a total of 680 members, making it one of the largest in the San Fernando Valley, said Tina Firestone, executive director of the Woodland Hills group.

Individually, the 54-year-old Woodland Hills chamber has 530 members and the 76-year-old Tarzana chamber has 150.