Half of all women who are victims of domestic violence will no longer qualify for legal aid under government proposals, leaving hundreds of thousands at greater risk of abuse, according to charities.

Ben Jamal, chief executive of the charity Domestic Violence Intervention Project, said analysis of their case files indicated that 50% of women victims would lose out.

Despite David Cameron's identification of the issue as a priority, experts say the government's proposed legal reforms run contrary to its pledges to tackle domestic violence. The Home Office action plan to end violence against women promises to "provide adequate support where violence does occur" and "take action to reduce the risk to women and girls who are victims.".

Three million women a year experience violence in Britain, a significant proportion of them domestic abuse, according to the government. Yet a coalition of specialists and women's rights groups say that proposals in the legal aid, sentencing and punishment of offenders bill, which has a third reading in the Commons this week, will seriously undermine its strategy on reducing violence against women.

Emma Scott, of campaign group Rights of Women, said the planned reforms to save £350m a year in legal aid would have a "devastating and disproportionate impact" on women. She added: "In his press conference announcing the legal aid bill David Cameron said that he wanted families to feel safe in their own homes, yet it will leave many at greater risk of violence and abuse, trapped in violent and abusive relationships and at greater risk of post separation violence."

"The reforms demonstrate a total lack of awareness and understanding of the dynamics and nature of domestic violence and the experiences of women affected by it."

Officially the government's position is that legal aid will be available to victims of domestic violence. But groups point to the government's decision to effectively change the definition of domestic violence by upping the type of evidence required to substantiate allegations, making it harder to qualify for legal representation.

Under the proposals "only women who can prove a high risk of violence" such as having secured a conviction against their perpetrator or have been referred for a risk assessment will be eligible for legal aid.

"They will put legal aid for family cases out of scope for the majority of women who have experienced violence and abuse," said Scott.

Jamal added: "Officially the government says one thing, but in reality they have drawn down the definition so narrowly that significant numbers of women are no longer eligible."Experts argue that other evidence including GP records, 999 call outs, social services and information from housing agencies should also be allowed.

Jamal also warned that alleged perpetrators will lose legal aid, raising the possibility that victims of domestic violence abuse will be cross-examined in court by their alleged attackers.