A 90-year-old Saudi man has married a 15-year-old girl after paying her family a dowry of $17,500 but the girl barricaded herself in her room for two nights before fleeing back to her parents' house.

The case sparked criticism in the Gulf kingdom with human rights activists urging authorities to intervene "as soon as possible to save this child from tragedy".

The husband insisted the marriage was "legal and correct" and that he paid the dowry to marry the girl, the daughter of a Yemeni father and Saudi mother.

Although she escaped the bridal room, the man vowed to file a lawsuit against her parents if she did not return.

Zuhaila Zein el-Abedin, of the Saudi National Association for Human Rights (NSHR), stressed that marriage in Islam must be based on mutual consent.

She said the girl's parents were responsible and demanded the establishment of a minimal age of 18 for marriage.

In 2012, the case of Amina Filali, the 16-year-old Moroccan girl who took her own life after she was forced into marriage with the man who raped her, sparked an international debate about minors being forced into wedlock.

Ten million girls under the age of 18 are married every year. Former British prime minister Gordon Brown, who has been campaigning along with his wife Sarah for education in developing countries, disclosed that 1.5 million of them are under the age of 15.

Amina killed herself by swallowing rat poison in her hometown of Larache in northen Morocco. In 2011, she was raped by a man who was 10 years her senior. The family agreed with a civil court ruling that she should marry her rapist in order to preserve their honour. But in the aftermath of the tragedy, the father denied the claims and said they were "advised" by the prosecutor to arrange a marriage with the man.

Marriage is viewed in many Arab countries as a daughter's destiny. Relatives arrange marriages primarily to get rid of a mouth to feed and girls who refuse to agree to a forced marriage are often seen by their families as rebellious and shameful.

The UN said that about 5,000 women and girls around the world are murdered by their relatives each year for disobeying their families' wishes.

But many Islamic officials and clerics refuse to accept a state-driven legal ban on child marriage, stating it would contradict the Koran. According to Islamic law, as soon as a girl reaches puberty she can choose whether to go on with a marriage or not, without waiting for the legal age.

They stress, however, that a woman should not get married before she is physically and mentally ready, as Islamic law adds that a wedding should not take place until the girl is physically fit to engage in sexual intercourse.