NEW DELHI/MUMBAI - India's ruling party on Monday ordered one of its senior members to apologise publicly after he offered a reward for anyone who beheaded a Bollywood star of a movie whose portrayal of a Hindu queen and a Muslim conqueror has enraged Hindu activists.

Deepika Padukone, one of Bollywood's biggest earners, is the lead actor of "Padmavati", which is based on an epic poem. The film explores the relationship of a Hindu queen from the Rajput warrior clan and Muslim ruler Alauddin Khilji.

The movie was due to open on Dec. 1 but its producers postponed the release and two states, both ruled by Prime Minister Narendra Modi's Hindu nationalist Bharatiya Janata Party (BJP), banned it outright.

Modi's party has asked Suraj Pal Amu, a senior member, why he offered 100 million rupees ($1.54 million) on the weekend to behead both Padukone and the movie's director, Sanjay Leela Bhansali.

Members of hardline Hindu fringe groups and the BJP have criticised the film, accusing Bhansali of distorting history by showing the Muslim aggressor as the Hindu queen's "lover".

Bhansali was attacked on set in January by a Rajput organisation. Some Rajputs believe that the queen chose self-immolation to reject the Muslim king's sexual advances.

"We will not tolerate any violent remarks from our party members, but we also want the director to respect India's history," said Anil Jain, the head of the BJP's state unit in Haryana, to which Amu belongs. He said the party was considering legal action.

Haryana police did not respond to requests for comment.

Officials at the Ministry for Information and Broadcasting said Hindu groups and some members of the ruling party had spread rumours about the film, which no members of the public and government had yet seen.

Keshav Prasad Maurya, deputy chief minister of Uttar Pradesh, India's most populous state, said he would not permit the movie's release unless scenes showing the queen in a "poor light" were deleted.

"How can a Muslim aggressor be portrayed as the real hero and the Hindu king and queen as victims This is factually incorrect," said Maurya.

Indian films that touch upon the historical relationships of Hindus, India's majority religion, and Muslim leaders are often controversial.

The head of the Central Board of Film Certification, Anurag Srivastava, said Padmavati's producers had applied on Nov. 10 to release the film, but the application was denied because producers did not clarify whether the film was based on fact or fiction.

Censorship of films can be highly charged. The government in August dismissed CBFC's chairman after criticism from Bollywood film-makers angered by attempts to sanitise art and popular culture.

Viacom 18 - a joint venture between Viacom Inc and Reliance Industries' RELI.NS Network 18 - is the studio behind the film, which analysts estimate cost some $23 million.

A senior police official in Mumbai said they had offered increased security to Padukone and Bhansali.

(Editing by Tommy Wilkes and Nick Macfie) ((Rupam.Jain@thomsonreuters.com; +91 11 49548039;))

Reported by Rupam Jain and Shilpa Jamkhandikar