"If they want to ask me anything...If they want to ask me any question whatsoever that they think...I can answer," 46-year-old Tarar told an Indian TV channel.
Her remarks came a day after Delhi Police registered a murder case on the basis of a medical report that concluded Tharoor's wife Sunanda Pushkar's death was due to poisoning.
Tarar, who was accused as an ISI agent by Tharoor's deceased wife Sunanda just before her death, said she shouldn't have replied to Sunanda's tweets.
52-year-old Sunanda was found dead in a 5-star hotel in South Delhi on the night of January 17 last year, a day after her Twitter spat with Tarar over an alleged affair with Tharoor.
A Congress MP from Thiruvananthapuram, it was Thaoor's third marriage to Sunanda and her third.
Sources said an investigation team is likely to question Tharoor, his relatives and personal staff along with the employees of the five-star hotel where she was found dead.