U.S. candy and snacks group Hershey and South Korea's Lotte Confectionery will set up an $80 million joint venture to make chocolate in China, aiming to boost share in a market dominated by Mars.

The deal potentially opens the door on a huge market for the maker of Hershey's Kisses and Reese's peanut butter cups as it faces higher costs and fiercer competition in the U.S..