Fish breeder Chan Sai Chuin's wife Chin Pek Nyen said the militants had not set any particular day for their November deadline but warned her they would kill him if the full ransom of RM 3 million (about $910,000) was not paid, the Malaysian Star reported.
She said the Abu Sayyaf gunmen made the threat during a call on Thursday night.
"They told me that they will send back Chan's head if I fail to pay the ransom," Chin, 42, told a press conference in Kuala Lumpur where she appealed to the state and federal governments to do more to secure her husband's freedom.
Abu Sayyaf gunmen made the threat during a call
Chan, who is from Perak, was abducted by the Filipino militants from his fish farm June 16 and is currently being held in an undisclosed location in the southern Philippines island of Jolo.
Chin said the gunmen had refused to allow her to speak to her husband since July 27 and she could not say for certain if he was safe and unhurt.
Chin said she had offered herself as hostage so she could be with husband and not "worry" about raising the ransom amount. Chin hoped that Chief Minister Musa Aman and Prime Minister Najib Tun Razak would help secure Chan's release.
Abu Sayyaf gunmen are also holding a marine policemen, Zakiah Aleip, 26, who was abducted from Mabul island July 12.