An official from the traffic department said the Border Roads Organisation (BRO), which maintains the highway, was undertaking hectic efforts to open the road. But bad weather was hampering the work.
"Because of continuing landslides and shooting stones in Panthal area near Ramban town, it is not advisable to allow vehicular movement on the road," said the official.
Around 350 trucks and some passenger vehicles have been stranded on the highway for the last four days, but all were parked at safe spots between Ramban and Udhampur towns.
"Adequate arrangements of food and other requirements have been made for the stranded passengers by the civil administration," the officer said.
Hundreds of Kashmir Valley-bound passengers were held up in the state's winter capital Jammu. But many of them were facing problems as they lacked money for their stay and food.
A police officer said several stretches of the highway were slippery as the snow had frozen into ice. "Our first priority was to get the stranded vehicles cleared from the highway," the officer said.
The Jammu-Srinagar highway is a double lane road. But at some places it gets narrower because of landslides.
The minimum temperature in Srinagar, the summer capital, was minus 2.5 degrees celsius Wednesday. It was minus 14 degrees in Leh and minus 15 in Kargil."Rain and snowfall are expected across the valley and Ladakh region during the next two days but they would be mild," said Sonum Lotus, director of the weather office in Srinagar.
The authorities have issued a high alert for possible avalanches in the higher reaches of the valley and asked residents there to remain indoors or to move to safer places.