The enraged wife was arrested yesterday in a suburb of the capital Kuala Lumpur, after her husband filed a police report, local district police chief Abdul Rahim Abdullah told AFP.
The victim was found and freed a few hours later.
Abdul Rahim said the husband was speaking with his lover on the phone last week when he suddenly heard his wife get on the line.
"According to investigations, the wife and her brother had found the man's mistress and made him listen while the two tortured and beat up the mistress before hanging up," he told AFP.
He declined to give any details on the people involved in the case.
Abdul Rahim said the wife called her husband again the next day and let him speak to his mistress, who complained of being beaten and having her hair cut off.
"The wife later met her husband on Sunday and showed him several pictures of his lover, who appeared to be tied up," he said.
"She also demanded a 50,000 ringgit (USD 16,800) ransom if he wanted to see the mistress again but the police managed to track the wife down before the situation got any worse," he added.
He said that police had also arrested the brother and four accomplices whose role in the case he refused to specify.