Nam Sang Wai is a wetland area in San Tin, New Territories, Hong Kong to the north of Yuen Long.^[1] It is considered ecologically important, and serves as a stopping place for migratory birds. It is also a popular recreational destination, especially on weekends.

Since the 1990s, various development proposals have been made at Nam Sang Wai by a consortium of Henderson Land and KHI Holdings Group. These plans have been challenged by environmentalists, politicians, the Agriculture, Fisheries and Conservation Department, the World Wildlife Fund, the Conservancy Association, and the Town Planning Board.

Nam Sang Wai covers a roughly triangular area. It is bordered by the Shan Pui River in the west, separating it from Yuen Long Industrial Estate, the Kam Tin River in the east and a branch of the Kam Tin River in the south.

It is home to many birds, including seagulls, northern pintails (Anas acuta), yellow-nib ducks (Anas zonorhyncha) and black-faced spoonbills (Platalea minor).^[2] Flora includes reeds and mangroves.^[3]

In what is considered to be a landmark case in the history of Hong Kong’s planning law regime, the Privy Council upheld the decision of the Town Planning Appeal Board approving development of a large scale residential, golf course, and nature reserve at Nam Sang Wai with conditions.^[4] The validity of planning permission was extended three times. In late 2010 a further extension was denied by the Town Planning Board.^[5]

The area is threatened by illegal logging and by fires (see below), on land owned by the Nam Sang Wai Development Company, that environmental advocates called "suspicious" and "professionally started".^[6][7]

The area is popular for recreational cycling. A proposal was made for a cycle track loop, but this has not been built.

Nam Sang Wai has been the subject of various residential development proposals.

Nam Sang Wai has been subjected to repeated fires regarded as suspicious by authorities. Commentators have alleged the fires have been set by arsonists attempting to reduce the environmental value of the area.^[6]

A suspicious fire occurred in 2010. Another fire on 21 December 2016 scorched an area "larger than the size of a football pitch".^[6] A series of fires appeared again in 2018, the first two happening on 12 and 13 March. The Fire Services Department considered these suspicious, and the Hong Kong Police Force are investigating possible arson.^[13] Another fire was discovered on 22 March,^[14] followed by yet another on 2 April .^[15] A video clip later emerged in local media showing two potential witnesses at the scene, even though the Hong Kong Police said they found no CCTV footage at the site.^[16]

A small boat in the southern part of Nam Sang Wai serves as a ferry across the Kam Tin River towards the village of Shan Pui Tsuen, north of Yuen Long Kau Hui.^[17]

A road, the Nam Sang Wai Road, runs along the eastern edge and most of the western edge of Nam Sang Wai.

Nam Sang Wai is in Primary One Admission (POA) School Net 74. Within the school net are multiple aided schools (operated independently but funded with government money) and one government school: Yuen Long Government Primary School (元朗官立小學).^[18]

• Mai Po Marshes
• Hong Kong Wetland Park
• Fung Lok Wai