Nepal's new prime minister has taken the oath of office and appointed the leaders of groups that are protesting the new constitution as his deputies.

Prime Minister Khadga Prasad Oli was sworn in by President Ram Baran Yadav on Monday a day after he was elected in Parliament with support from smaller parties.

He appointed two deputy prime ministers, Bijaya Gachchedar, who leads one of the Madhesi ethnic groups, and Kamal Thapa of the party that is demanding Nepal be restored as a Hindu state.

Protests by the Madhesis in southern Nepal have disrupted traffic at border points with India, cutting off fuel and other supplies to most part of the Himalayan nation.

Oli has vowed to work to resolve the crisis.