A man has been arrested in the southern province of Vinh Long following a complaint by his 16-year-old daughter that he had raped her many times in the last four years.
The police confirmed Tuesday that they are holding the 39-year-old suspect.
The girl's mother, 43, who has not been identified, told Tien Phong newspaper that she did not know about it until officers came home with an arrest warrant.
She claimed she had been too busy working and did not pay much attention to her daughter.
Raping a child under 16 multiple times is punishable by death under the Penal Code.
A report from the Ministry of Public Security in January said 9,920 Vietnamese children suffered from various forms of abuse, including violence, sexual abuse and trafficking, in the past five years.
Often, the perpetrators were the victims' family members.
One girl in the Mekong Delta’s Hau Giang Province was raped by her grandfather in early 2014 when she was seven.
Another girl who is staying in a Ho Chi Minh City shelter for rape victims was assaulted by her father when she was 13.
The father was heavily indebted due to soccer gambling losses, and his friends said he should have sex with a virgin to end his bad luck.
Schools in Vietnam, where child rapes account for nearly two-thirds of the average of 1,000 sexual assaults reported each year, do not focus on gender and sex education to enable children to protect themselves.
Many parents meanwhile are afraid that discussions about gender and sex are tantamount to teaching children how to have sex.