The way that the issue of women and the global trafficking industry is framed lags behind the reality, says Cathy Zimmerman, a global trafficking researcher at the London School of Hygiene and Tropical Medicine.

"I think the word trafficking still means sex trafficking for many funders and the public at large, largely to do with the exposure of the brutality and enslavement of women by sex traffickers within the past few decades," she says.

"When we at the school first started looking at this issue, we focused exclusively on sex trafficking, largely because nobody was identifying or assisting people trafficked for other purposes, but now this is shifting. There is a growing realisation that labour trafficking is a much wider, more subtle phenomenon, and, in terms of numbers, an extensive problem affecting women from all over the world."

In response to this shift in emphasis, the UK's Department for International Development (DfID) and the International Labour Organisation (ILO) have launched a £9.75m anti-trafficking initiative aimed at helping to prevent 100,000 south-east Asian women from being trafficked into forced labour in the garment industry and as domestic workers.

Central to the Work in Freedom programme's strategy is the idea that the solution to stopping women from being trafficked is not to stop them travelling in the first place – the cornerstone of much anti-trafficking work focusing on women and children to date.

Instead, the initiative will seek to provide women with skills, pre-departure training and support to help them avoid being trafficked, and secure legal contracts and decent wages in destination countries. The initiative also intends to help thousands of girls under 16 stay in school, so they are not compelled to migrate for work.

"It's not enough to tell these women 'Don't leave', because it's very clear that they don't feel that this is an option," says Zimmerman, whose school is a partner in the programme. She points out that the school's early research into women and trafficking in Europe showed that almost 40% of women who were trafficked for sexual exploitation were single parents.

"We need to look at why women are leaving, what are the different pressures that men and women face when they make this choice to migrate and how trafficking happens at key points of vulnerability along the way."

Zimmerman says that in the panic to try to stop women falling into the hands of traffickers, the concept of protecting their right to work was lost. "What must not be forgotten in the anti-trafficking debate is how important it is that women have job opportunities, which are safe," she says.

"I think for many governments and funders, there was this idea that the solution to the problem of trafficking was to close down migration routes to women or to scare them away from looking for work away from the home, but this doesn't work."

For one thing, Zimmerman says, such an approach pushes more women to migrate under increasingly risky or dangerous circumstances. "Then you have a situation where you're not addressing the reasons why these women need to leave in the first place," she says, "be it poverty, domestic violence, discrimination. There is also the growing understanding that stopping women from migrating leaves them far more vulnerable to other risks, such as early marriage."

At the launch of the DfID event this month, Manju Gurung, founder of Pourakhi, a Nepalese NGO working with migrant women in Nepal, explained how this dynamic has played out in her country. Recent changes in Nepalese law ban women from migrating to work as domestic employees, usually in the Middle East, until they reached the age of 30.

"In the name of protection, the government put these bans in, but now because of this age bar, women are instead migrating through undocumented channels. Because of this they are more vulnerable, as they're not able to enjoy the rights provided by the Nepalese government."

Women who migrate through unofficial channels first encounter a labour broker, then receive a fake contract and cross the border into employment with no official documentation or visa.

"Many face beatings … sexual exploitation, labour exploitation and long working hours. My organisation runs a shelter, and we receive many women who face violence in their destination country. They come with unwanted pregnancy, mental health problems, these are the kinds of things they are facing during this [undocumented] migration."

Also at the launch was Bandana Pattanaik, international co-ordinator at the Global Alliance Against Traffic in Women. She says greater understanding of the extent of labour trafficking – which, according to the ILO, affects 21 million people a year – will help find solutions that keep women safe while allowing them to take work opportunities that could benefit themselves and their families.

"I think the launch of initiatives … give us the opportunities to look at women … not only as potential victims but as workers with rights," she says. "I think it's a good moment that we are looking at … trafficking not only as violence against women but also as a labour issue."