China has launched an extraordinary bid to prevent NSW MPs from attending a briefing on the international human organ trade at Parliament House by implying that economic cooperation with Australia and NSW could be threatened if they show up.

In a letter to the president of the NSW Legislative Council, Don Harwin, on Monday night, the Chinese consul general in Sydney, Li Huaxin, says the involvement of the religious group Falun Dafa in the briefing is of "deep concern" and asks him to forward the correspondence to all NSW MPs.

Don Harwin, president of the NSW Legislative Council, received the letter from the Chinese consul general. Credit:Dallas Kilponen

Falun Dafa is a branch of Falun Gong, which has been banned in China since 1999. Falun Gong accuses the Chinese government of murdering its practitioners to harvest their organs.

It says this explains why there are thousands of organs transplanted in China each year despite so few people being on the official donor register. However, China has said the main source of its organs is death row prisoners.