The National Highway Authority of India and the Border Roads Organisation will jointly undertake the construction of another highway between Sevoke, near Siliguri, to Nathula in October this year.
The chief engineer of BRO's Project Dantak in Sikkim, Brigadier MS Pillai, told reporters that the project would be completed by 2009 at the cost of Rs 700 crore.
The existing highway between Siliguri and Gangtok, the only road that connects Sikkim to the rest of India, is vulnerable to climatic vagaries like landslides during the monsoons.
The NHAI will construct the highway from Sevoke to Gangtok while the BRO will build a double-laned road from the Sikkimese capital to Nathula border, Pillai said.
The project acquires significance as Nathula was reopened for border trade between India and China on July 6 and the need for an improved road facility along the route is being widely felt.
Pillai said Rs 500 crore will be spent on the construction of the highway between Sevoke and Gangtok and another Rs 200 crore on building the road between Gangtok and Nathula.
He lauded the BRO's taskforce that built and repaired all the approach roads between Gangtok to Nathula in less than a year despite harsh weather conditions and difficult terrain.