By Piya Sinha-Roy

LOS ANGELES (Reuters) - Actress Katie Holmes faces two strong adversaries in her legal fight for sole custody of 6-year-old daughter, Suri, as she battles estranged husband Tom Cruise and his Scientology religion, experts said on Monday.

The "Dawson's Creek" actress, 33, made headlines last week when she filed for divorce from "Mission: Impossible" actor Cruise after nearly six years of marriage and one child.

While Holmes, Cruise and representatives for both have remained quiet about the reasons for the high-profile split, speculation in the media is that Suri, now at the age when she begins a formal education, and the Church of Scientology, of which Cruise is a key member, are central to the breakup.

"What's interesting is that there's three players in this case - the mother, the father and this very controversial concept of Scientology," said New York-based divorce lawyer Lubov Stark.

"The daughter is in the middle of this whole divorce. She seems to have been raised in Scientology up to this age, so if the judge comes in and gives custody to Katie Holmes, she can change (Suri's) religion," Stark said.

The Church of Scientology was founded by science-fiction writer L. Ron Hubbard, and it describes its practices as a religion. The organization believes man is an immortal being whose experience extends beyond one lifetime, and it has attracted followers including Cruise and John Travolta.

But some observers - including media mogul Rupert Murdoch - liken it to a cult. Critics think the group coerces followers to think like they do, and they accuse Scientologists of harassing people who seek to quit.

On Sunday, following last week's news of Holmes' divorce filing, Murdoch took to Twitter and called Scientology "a very weird cult" and Scientologists "creepy, maybe even evil."

SCIENTOLOGY AND THE MEDIA

"Scientology is a potentially unsafe, if not dangerous, organization," said Rick Ross, a New Jersey-based expert on cults and controversial movements who has served as an expert witness in court cases.

"I've received complaint after complaint over the years from former members."

Ross said Holmes' custody battle could hinge on whether Cruise decides to fight Holmes for custody of Suri and how much information comes out about Scientology practices, which the Church may not find in its interest.

Representatives for the Church did not respond to Reuters' requests for comment.

Ross said it is unlikely the Church would get directly involved in the custody battle as it could bring negative publicity, but he believed members could leak information to "intimidate or discredit" Holmes.

Lawyer Stark said custody proceedings will differ substantially depending on whether they take place in New York, where Holmes filed, or California if Cruise can get the case moved to the state in which he resides.

In California, Stark said the courts presume joint custody, leading to a greater likelihood a judge would give both Holmes and Cruise the ability to make decisions for Suri.

"If the judge says they should have joint custody in California, then Katie would not have the ability to take Suri out of this religion altogether," said Stark.

In New York, the courts look at the best interests of a child and who's going to make decisions and care for the youngster. In that case, a judge might be asked to consider Cruise's religion, although the possibility appears remote.

"Religion can always come into it, but it's rare for a custody battle," said Josh Forman, a matrimonial attorney and partner at Chemtob Moss Forman & Talbert in New York.

Like Ross, Forman believed any negative publicity from a long trial might lead to a private settlement.

"I don't think it would be very good for Tom's career if he is seen as having a huge, dragged-out custody battle with Katie. I think they should really settle, and I see this as settling."

(Editing by Bob Tourtellotte and Cynthia Osterman)