Customs officers on Thursday said they had arrested a 35-year-old woman who is suspected of smuggling a tonne of agarwood into Hong Kong from Nansha.

It was the largest seizure of agarwood in history and the first case of smuggling the product by sea, Customs officers told a joint press conference with the Agriculture, Fisheries and Conservation Department (AFCD).

Officers said they seized the endangered species in a 20-foot container at the Tuen Mun River Trade Terminal, with a market value of around HK$18 million.

"In this case, we noticed that agarwood is a kind of very rare wood, and its demand is very high and its value is very high," said Lau Yuk-lung, an acting senior superintendent with customs.

"It can be used to produce different kinds of products like essential oil, some ornaments or decorations, so it has been used by different criminals for making profits."

Meanwhile, the AFCD said it would step up inspections at border checkpoints to combat the smuggling of agarwood.

"We also conduct regular education campaigns to educate the public about the regulation of agarwood and other endangered species," said the AFCD's endangered species protection officer Chan Hon-ki.

Chan added that agarwood is protected under Hong Kong law and trees are often illegally cut down due to their high value and demand.