The Academy Award-winning actress told a fundraising dinner Wednesday night marking the 20th anniversary of the UN Trust Fund to End Violence against Women, that she has been speaking out ever since "to be a voice for the women who don't have a voice."

According to the United Nations, today one in three women worldwide have experienced physical or sexual violence — mostly by an intimate partner.

Kidman, who is a goodwill ambassador for UN Women, urged the guests "to undo your wallets," saying these women and girls "need us who have the ability, who have the money," to help them.

UN Women said the dinner raised over $105,000, including a $50,000 donation from Kidman.

Over the past two decades, UN Women said the trust fund has provided support to 426 organisations in 136 countries and territories with grants totaling more than $116 million.

The fund's grants have risen from $1 million in 1997 to supporting $57 million in grants in 2016.

The programs it supports focus on preventing violence, implementing of laws and policies, and improving access to vital services for survivors.

UN Women's Executive Director Phumzile Mlambo-Ngcuka said: "We know that these vital investments in initiatives to end violence have high returns and have already made a difference to millions of women and girls."

But she said much more needs to be done requiring substantial funding to "bring the scourge of violence against women to an end."