Nepal last year introduced a ban on women working as domestic helpers in the Gulf, one of various laws passed over the last decade to protect female migrant workers from sexual exploitation.
"These bans are ineffective and create the consequence that women migrate through irregular channels and become victims of trafficking," said the UN Special Rapporteur on the human rights of migrants, Felipe Gonzalez Morales.
"They (the government) don't realise it's discrimination, but these policies are inconsistent with international law and should be lifted."
The vast majority are men working in construction in the Gulf and Malaysia, but around 20,000 women also left that year despite various laws that restrict female migration.
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In recent years Nepal has introduced a minimum age limit for female migrant workers, prevented mothers with children under two from leaving the country for work, and most recently banned women from domestic work in the Gulf, though enforcement has been patchy.
"The government is trying to make a statement that they are protecting (women). But this can be done through other means," Morales said.
Nepal's government has been criticised for failing to protect migrant workers from exorbitant fees charged by recruitment agencies that leave them mired in debt and trapped in jobs overseas.
In 2015 it banned agencies from charging migrants for flights and visas, but enforcement has been weak. Some suspect authorities are reluctant to clamp down on the lucrative industry.
"Everyone agrees that there is a big problem in the recruitment process, but there doesn't seem to be a concrete plan to take steps to have the employers paying for this, which would be the solution according to international standards," said Morales.
Political instability in Qatar and an economic slowdown in Saudi Arabia -- the two largest recipient countries of Nepali workers -- saw the number of new arrivals from Nepal slump at the end of last year.
Remittances declined by 1.4 percent in the same period, a tiny drop that still resulted in Nepal's current account balance slipping into the red, according to central bank figures.