An autopsy report has said Indian minister Shashi Tharoor's wife, who was found dead in a luxury hotel after accusing her husband of being unfaithful, suffered an "unnatural, sudden death".

"More tests" are needed to determine the final cause of 52-year-old Sunanda Pushkar's death and the results will not be known for two to three days, Sudhir Gupta, one of three doctors who carried out the autopsy, told reporters.

Human Resources Minister Mr Tharoor found the body after he returned from a Congress party meeting late last night, his private secretary Abhinav Kumar said.

"There were no signs of any foul play," Mr Kumar said. "She seemed to be sleeping in a normal way but later it was found she was dead."

Officials said it was not known yet how she died. She had been taking medications for various illnesses, including tuberculosis, according to local media.

"Whatever is destined to happen will happen, will go smiling," were among Ms Pushkar's last tweets, The Times of India reported.

Mr Tharoor was admitted this morning to the same hospital where his wife's body was being held, after complaining of "general chest discomfort", a hospital spokeswoman told reporters.

But his test results were normal and he would be released soon, she said.

The couple wed in 2010 and were well known on the Indian social scene but there had been rumours for a number of months of marital problems.

Late Wednesday a series of messages appeared on the Twitter account of Mr Tharoor, a former high-flying UN diplomat, novelist and key government spokesman.

They showed private exchanges purportedly between the 57-year-old minister (@shashitharoor) and Pakistani journalist Mehr Tarar (@mehrtarar), in which she professed her love for him and he said his wife had discovered their relationship.

Mr Tharoor, known as "Mr Twitter" with more than two million followers, quickly responded by saying his account was "hacked", but Ms Pushkar spoke to newspapers saying she sent the messages.

She also raked up a corruption scandal related to the Indian Premier League (IPL) cricket tournament that almost wrecked Mr Tharoor's career in 2010 and led him to resign from the cabinet.

Mr Tharoor issued a joint statement Thursday in which he blamed unauthorised tweets and distorted media reports for the "unseemly controversy".

The statement said the couple were "happily married".

Mr Tharoor and his wife, the mother of an adult son from a former marriage, had been staying at the hotel since Thursday as work was being done to their home.