WELLINGTON, July 30 (Xinhua) -- The ivory key tops of a 123-year-old family heirloom piano were removed by New Zealand authorities due to violation of ivory trade rules, media reported on Sunday.

According to New Zealand's Department of Conservation (DOC), the piano was "illegally exported from the UK and illegally imported to New Zealand" because it was "imported without the required documentation."

"Under the Trade in Endangered Species Act 1989, it is the responsibility of the person importing the goods to ensure they have the correct documentation for import and export of items that include endangered species," said Lou Sanson, DOC's director-general, in a statement.

The piano belongs to Julian Paton, a professor at University of Auckland, who immigrated to New Zealand from Britain with his family last year.

"We are disappointed and horrified as a family at the bureaucracy," Paton told local website stuff.co.nz, adding that if they had known they needed further documentation, they would have completed it.

Apart from new key tops, Paton were also told to pay for the ivory removal and dumping. He felt that was unfair and decided to fight DOC's administration fees.

New Zealand is part of an international agreement called the Convention on the International Trade in Endangered Species of Wild Fauna and Flora (CITES), which aims to protect endangered animals and plants.