Security has been stepped up in Nepal ahead of the promulgation of the Himalayan nation's new federal constitution, which is protested by smaller political parties and ethnic groups.

Police official Kamal Singh Bam says thousands of officers are guarding the streets and passengers on highways are being checked.

Bam says police have responded to reports of bombs being found in Kathmandu but they all turned out to be a hoax.

Security is also high around the Constituent Assembly building in the capital, where president will promulgate the new constitution later Sunday.

Opposition parties called a general strike to protest the constitution but it had little effect on the traffic.

Sunday and Monday are public holidays.