Marzia Basel expressed her views at an international conference on violence against women held in Rome this week.
"Violence suffered by women in Afghanistan is a dramatic problem that should be tackled in a serious way," Basel told the conference at the Italian foreign ministry on Thursday.
The G8 International Conference on Violence Against Women was hosted by Italy, which is the current president of the G8 group of the world's seven most industrialised nations plus Russia.
Basel said she was "surprised" by a law signed last Sunday by Afghan president Hamid Karzai, aimed at preventing violence against women in the country.
But she described it as "an important step forward by the government to defend Afghan women."
"At last, penal sanctions have been enacted against those who commit crimes against women," said Basel.
Drafting of the law began two years ago.
It is based on articles of the Afghan constitution which enshrine the duty of the state to respect and protect the "inviolable" liberty and dignity of all of its citizens", and "ensure physical and psychological well-being of a family, especially of child and mother, upbringing of children and elimination of traditions contrary to the provisions of Islam."