BEIJING - China's Ministry of Commerce Thursday defended the country's tariffs on out-of-quota sugar imports, saying they will help maintain trade order.

The move announced by the ministry Monday will also ensure a fairer market, which serves the long-term interests of all parties, the ministry spokesman Sun Jiwen told reporters at a regular press conference.

Sun said the ministry strictly followed World Trade Organization rules during the investigation, which was in response to pleas by the domestic industry, and found that increasing imports were causing serious harm to local producers.

China decided to begin three-year duty on out-of-quota sugar imports to protect the domestic industry. The duty will be set at 45 percent from May 22, 2017 to May 21, 2018, and be reduced to 40 percent and then 35 percent in each subsequent year.

The duties do not cover imports within the quota of 1.95 million tons for 2017.

Last year, China imported 3.06 million tons of sugar, down 36.8 percent from 2015.