Police in Ho Chi Minh City are investigating a case in which a woman says she was raped by her South Korean boss at his home.
The 56-year-old man has been detained, news website Zing reported.
The woman, who worked as a personal assistant for the man at a company, reportedly followed her boss to his apartment in Phu Nhuan District after a party on the night of July 15.
He allegedly asked to have sex with her but she refused and tried to resist him.
The woman said he then raped her.
She only managed to escape after pretending to have abdominal pain and asking the man to take medicated oil.
The report said after she ran downstairs and screamed for help, guards and residents called the police.
The foreigner has reportedly admitted to his act. Police are waiting for results from medical examiners to take necessary legal actions.
Around 1,000 sexual assaults are reported each year in Vietnam, where surveys found girls and women are usual victims of sexual harassment in public places and the workplace.
The country developed the first code of conduct on workplace sexual harassment last year with support from the International Labor Organization.
A government report in 2012 showed that most of the victims of sexual harassment in the country are female workers aged between 18 and 30. Many chose to keep silence out of shame and the fear of losing jobs.