Nepali police have shot and killed an Indian citizen at a border checkpoint as they tried to clear protesters whose blockade has strangled Nepal's fuel supplies and badly damaged relations between the neighbours.

Nepal has faced an acute fuel crisis for more than a month since protesters in the lowland south, angered that a new constitution fails to reflect their interests, prevented supply trucks from entering from India.

Many in Nepal see India's hand in the protests although it denies any role.

With the landlocked Himalayan nation of 28 million recovering from its worst earthquake on record, the government has turned to China for extra fuel.

Officials said some Chinese oil was due to arrive in Kathmandu late on Monday.

Hundreds of stick-wielding protesters battled with police near the border crossing, known as the "friendship bridge", in Birgunj district.