Guerrilla action by Maoist rebels is delaying construction of Nepal’s US$464M Melamchi water supply project which includes a 26.5km long water tunnel.

Dinesh Chandra Pyakurel, a senior official with Nepal’s housing and physical planning ministry, confirmed that tunnel construction has been held up because contractors have been unable to transport explosives to the tunnel site amid security concerns.

The tunnel, running from Ribarma to Sundarijal, would divert 170M/l of water a day from the Melamchi river to the Nepalese capital, Katmandu. Maoist rebels, who recently bombed one of the nine bridges that help form the 23km long access road to the tunnel site, have warned of further attacks.

The guerrilla action has already led to the completion of the project being postponed from 2006 to the end of 2008.

Mr Pyakurel said: "The situation on the project site is very volatile and we are finding it difficult to go ahead with the civil works."

The tunnel is a key element of the water supply scheme which is intended to restore regular water supplies to Katmandu’s 1.5 million population.