Customs officers in east China's Shandong province showcase the butterfly specimens confiscated over the past month on April 5, 2016. [Photo: CFP]

Customs officers in east China's Shandong province have confiscated some 2,800 butterfly specimens illegally imported into the country on Tuesday, 1,180 of which are protected species under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

This is the largest smuggling case of butterfly specimens since China joined the convention in 1980.

Customs officers intercepted a suspicious package from Malaysia as it passed through X-ray examination in early February.

The customs declaration described the contents as one-piece dresses, but they turned out to be 261 butterfly specimens.

The officers have since found four more packages from Malaysia and Indonesia.

All four packages were sent to the same suspect, who has been ordering butterfly specimens overseas over the Internet for the past year.

The suspect decorated the specimens and then sold them at a profit.

Further investigations are underway.