The country's quarantine authority is stepping up efforts to detect harmful non-native species, as strengthened global interactions have brought more insects and viruses that may pose severe threats to the country.

More than 22,000 packages of plant seeds and sprouts amounting to 80 metric tons were intercepted at China's entry ports in an eight-month campaign that cracked down on illegally bringing and mailing seeds and sprouts into the country since March, and nearly 14,200 of them were found to contain harmful species.

The number of seeds and sprouts illegally carried and mailed into China has increased rapidly as the country's global interaction grows through travel and trade, and as shopping from overseas e-commerce platforms matures, said Chen Maosheng, deputy director of the department of supervision on animal and plant quarantine under the General Administration of Quality Supervision, Inspection and Quarantine. The means of carrying such contraband also is becoming subtler, Chen added.

"But travelers and shoppers must be aware that the invasive species carried by the seemingly harmless seeds and sprouts may do severe harm to our country's agriculture, animal and fishery industries, as well as food safety and ecological security," Chen said during a media briefing in Shanghai on Tuesday.

He said the two main categories intercepted in the campaign were live creatures, such as spiders and tortoises, and succulent plants, which have become popular among amateur plant collectors in recent years.

"Some of the animals have extraordinarily strong surviving and reproductive abilities. As they can quickly adapt to the new environment and are free from natural predators in China, they will make local species extinct and spread intestinal bacteria that are infectious to humans," Chen said.

As a defense system, China currently has a list of foreign plant and animal quarantine pests, and the number of harmful species is more than 400.Live animals, meat and dairy products, fresh fruits and vegetables, seeds and soil that may contain the harmful species are prohibited from being carried or mailed into the country.

"Cargo and luggage that contain the prohibited items are returned or destroyed as we step up efforts to block them from the country," said Li Jing, a spokeswoman for the administration.

"Those who intend to conceal banned items in their carry-on and checked luggage will face administrative penalties, fines of a maximum of 50,000 yuan ($7,700) and will have their names added to a credit blacklist. They may be held criminally liable if the item causes a major epidemic in the country," Li said.