Nepal has introduced women-only minibuses in its capital city, in an attempt to protect female passengers from sexual assault.

The initiative has begun with "women-only" signs being placed on four 17-seater minibuses and they will operate on key routes in Kathmandu during morning and evening rush hour.

"Groping and sexual assault is a problem for women who use buses, especially during peak hours when buses are overcrowded," said Bharat Nepal, President of the Bagmati Federation Transport Union, which introduced the service.

"This is our small initiative to make commuting safe and secure for female travellers," he added.

Only one of the buses currently has a female conductor, but he said the goal was to eventually employ an all-women crew.

In a 2013 World Bank survey, 26% of female respondents aged between 19 and 35 said they had experienced some form of sexual assault on public transport in Nepal.

In 2011, a 21-year-old Buddhist nun was gang-raped in a bus in eastern Nepal by five men, including the bus driver.

Complaints about groping prompted authorities in neighbouring India to introduce women-only carriages on the metro system in the capital New Delhi in 2010.