Bollywood's latest film about troubled marriages is showing to packed houses in India's cities, but it has not gone down well with millions in the conservative countryside where marital vows are still the basis of family values.

Kabhi Alvida Naa Kehna suggests that true love is more desirable than a bad marriage, a brave departure in an industry that has survived on making saccharine love stories with picture-perfect endings.

Critics say urban, multiplex audiences may have been able to identify with the film's taboo theme - thanks to their growing exposure to Western values - but in India's more conservative heartland the response has been cold.

"It's mature, bold and dares to say it loud and clear that a man and woman - both trapped in loveless marriages - have the option to start all over again. Or at least try to," film critic Khalid Mohamed wrote in a newspaper.

In the past, Bollywood's attempts at examining marriage and its shortcomings were subjects touched only by art house movies with little mass appeal.

Although there were rare attempts by mainstream filmmakers as well, none went the distance and questioned the relevance of marriage itself, as Kabhi Alvida does.

The film is about two seemingly happy couples who meet their soulmates outside marriage, forcing them to look at their relationships from a new perspective.

Kabhi Alvida is set in New York and revolves around the lives of a set of rich Indian immigrants, something that rural Indian audiences may also not have been able relate to.

Kabhi Alvida was certain to have raised the hackles of elderly Indians, but the young generation would identify with the stark realities of modern-day marriage, critics said.

"The film made a magnificent start, and is doing fabulously at big centres, with business at multiplexes proving to be superb," said trade analyst.

"However, it is not as strong at smaller centres."

Kabhi Alvida features two of Bollywood's biggest stars - Amitabh Bachchan and Shah Rukh Khan - and cost $4.5 million to make, expensive by Bollywood standards.

While it will depend largely on India's urban audiences to recover that amount, the film has done surprisingly well outside the country.

It earned a record $1.4 million in its opening week in the United States and is said to be bringing in the audiences, mostly Indian expatriates, in Britain and Australia as well.

"The director may say he is portraying a social reality, but the fact is this film sends out a wrong signal," said Nutan Bugde, a social activist and a mother of two daughters who watched the film in Mumbai, the home of Bollywood.

"The film will wrongly impact the youth and teach them that there is no need to make adjustments in a relationship."