Huriya Mashhoor told the AFP news agency she wanted to revive a bill that has lain dormant since 2009, which would have set the minimum age for marriage at 17, and amend it to raise the age to 18.
"We are asking to fix the legal age for marriage at 18, as Yemen is a signatory to the international conventions on children's rights," she said.
Eight-year-old Rawan was said to have died last week from internal bleeding after sexual intercourse, after having been married to a man in his 40s in the northeastern province of Hajja.
The provincial governor, however, on Saturday denied the reports that Rawan had died.
Mashhoor spoke a day after the government formed a committee to investigate the reports of the girl's death.
The governor of Hajja province told official news agency SABA that Rawan was still alive.
Ali al-Qaissi said "the young girl Rawan Abdo Hattan is still alive and normally lives with her family who, in turn, deny the whole thing".
But he added that "the young girl is currently in a social protection center after undergoing physical and psychological tests in a public hospital" in the area.
Before the denial from the governor, Mashhoor had said, "We do not have enough evidence at the moment."
"But I am worried that there could be an attempt to silence the matter, especially as it took place in an isolated rural area in Hajja province where there have been similar cases before.
"If the case was confirmed and covered up, then the crime would be more serious," Mashhoor warned.
Mashhoor has been involved in a campaign against the marriage of child brides in Yemen. There is no clear definition in the country of what constitutes a child, making it difficult to battle the practice.
European Union foreign policy chief Catherine Ashton urged the Sanaa authorities on Friday to investigate the case "without delay and to prosecute all those responsible for this crime".
Human Rights Watch said on Wednesday that 14 percent of girls in Yemen are married before the age of 15, and 52 percent before 18, citing Yemeni and 2006 data from the United Nations.
Marrying off young daughters is a way for poor Yemeni families to save on the costs of bringing up a child and earn extra money from the dowry given to a girl.
According to the UN about half of Yemen's 24 million people lack sufficient food and access to safe water.
SHI/SHI