NEW DELHI - India could bring in legislation to jail anyone who insults Mahatma Gandhi while state governments are moving to ban a biography that reviewers said showed the "Father of the Nation" was bisexual.

Gandhi led the campaign to end British colonial rule but lawmakers say his reputation is being besmirched by a new biography that suggests he had a homosexual affair with a German bodybuilder.

"Mahatma Gandhi is revered by millions, not just in India but across the world. We can't allow anybody to draw adverse inferences about historical figures and denigrate them. Otherwise history will not forgive us," Law Minister M. Veerappa Moily told the Indian Express newspaper.

An amendment to India's National Honour Act of 1971 could see Gandhi protected alongside the constitution and national flag, with any insults against him punishable by prison.

Pulitzer prize-winning author Joseph Lelyveld's biography, "Great Soul: Mahatma Gandhi and His Struggle with India", details correspondence in 1908 between the freedom fighter and Hermann Kallenbach, a German-Jewish bodybuilder.

Reviewers for US and British newspapers cited a letter in which Gandhi writes to Kallenbach about "how completely you have taken possession of my body" as proof of his bisexuality.

The biography showed that Gandhi was "a sexual weirdo", reviewer Andrew Roberts wrote in the Wall Street Journal.  

Lelyveld has denied his book says Gandhi was bisexual.

The Delhi high court ruled gay sex was not a crime in a landmark July 2009 judgement, but colonial-era legislation criminalising homosexual sex has not been repealed and relationships between gay couples are still taboo.

The western state of Gujarat, where Gandhi was born, banned the sale and distribution of the biography on Wednesday. The state of Maharashtra is also taking steps to ban the book, local media reported this week.  

"The people of Gujarat will never tolerate such insult to Gandhiji," said Chief Minister Narendra Modi, who leads the Hindu nationalist Bharatiya Janata Party in Gujarat.

Lelyveld's book is not the first to fall to Indian political or religious pressure. In October, a Rohinton Mistry novel, "Such a Long Journey", was removed from Mumbai University's syllabus following threats against the author from far-right political group Shiv Sena.

Maqbool Fida Husain, India's most celebrated painter, lives in exile in Dubai after Hindu nationalist groups threatened him for paintings of Hindu goddesses showing nudity.