Sister Donna Markham has been named as the new president of Catholic Charities USA (CCUSA), the first time a woman has occupied the post in the organisation's 105-year history.

CCUSA, based in Alexandria, Virginia, is the national office of more than 160 local Catholic Charities agencies nationwide, all of which are working to tackling poverty in America.

Sister Donna is an Adrian Dominican sister and clinical psychologist. She has a PhD in clinical psychology and is currently president of the Behavioural Health Institute at Mercy Health, one of the largest non-profit health systems in the US.

"There can be no greater call than to serve and advocate on behalf of persons who struggle to get by in a world where they are all-too-frequently relegated to the margins of society and where they long for dignity, hope and compassion," Sister Donna said in a statement.

"I feel blessed to walk among the many dedicated Catholic Charities workers across the country who daily make the Gospel come alive through their care for their sisters and brothers in need."

Sister Donna, who will start her new role in June, previously served on CCUSA's board of trustees for eight years.

The organisation reaches more than 9 million people in America each year, providing social services such as housing and family support services, regardless of religion.

The outgoing president, Father Larry Snyder, has been in post since 2005, and is moving to become vice-president for mission at the University of St Thomas in Minnesota. During his time as president he became a leading voice for the rights of the poor in US politics.