Fresh evidence implicating the Church of Scientology in the mistreatment and exploitation of some of its most loyal adherents will be aired on Four Corners tonight.

The allegations come just days before an expected Senate vote on whether to launch a Parliamentary inquiry into the church.

Tonight's program, Scientology: The Ex-Files, focuses on the stories of Australians and Americans who have left the church and are now speaking out. Some are taking legal action against the church.

The men and women featured in the program belonged to Scientology's elite unit of full-time staffers, the Sea Organisation - or Sea Org.

The allegations in tonight's program include first hand accounts that some women have been coerced into having abortions because the Sea Org does not allow its members to have children while they work in the organisation; that children as young as 15 are interrogated about their sex lives, asked to work excessive hours, and punished severely if they fail to meet targets for recruiting members of the public; and that 'public' Scientologists - Scientologists who live and work in the broader community - are pressured over long periods of time into donating their life savings to the church.

The church itself denies the allegations, and is vigorously defending the legal actions which are underway in the United States.

As a religion, the Church of Scientology is tax-exempt in Australia and the United States. In other countries - for example, the United Kingdom - it does not have charitable status.

The UK Charity Commission has determined that the Church of Scientology was not established for the public benefit.

Over the past year, the Church has opened a number of new churches around the world, largely it is believed, funded by tax-free donations from ordinary parishioners.

Tonight's program features an exclusive interview with a former rugby league player, Joe Reaiche, who played for Eastern Suburbs and Canterbury Bankstown in the 1970's.

Mr Reaiche, who now lives in America, was declared a "suppressive person" and expelled from the church in 2005.

He has not seen his children - who work in Hollywood and who remain public Scientologists - since then, and says he believes that they were warned not to contact him after he was declared a "suppressive person".

Mr Reaiche told reporter Quentin McDermott: "You don't do that to a parent."

Church of Scientology spokesman, Tommy Davis, denies that the church has a policy of disconnection.

He says that members of the Church are free to maintain contact with relatives who have been expelled, but acknowledges that they would not then be welcome in the Church.

Mr Davis told Four Corners: "If somebody is expelled from the church, anybody who insists on continuing to be connected to somebody who's been expelled from the church would be told that as long as they maintain that connection they're not welcome in the church."

Tonight's program features interviews with three members of the Anderson family from Canberra.

Liz Anderson, who left the church last year, has not seen her eldest daughter Fiona since 2005, when Fiona was posted overseas by the Sea Org in Sydney to join the Sea Org at its base in Clearwater, Florida.

Mr and Mrs Anderson arranged for their youngest daughter Jordan to leave the church last year. Both Jordan and her older sister Fiona joined the Sea Organisation aged 14.

Jordan tells Four Corners that she was asked to work excessive hours for minimal pay - and once worked 72 hours straight without sleep.

The church's senior spokesman, Tommy Davis tells Four Corners that if that were the case, it would be "utterly and completely unacceptable".

Tonight's program also highlights the issue of alleged "coerced" abortions within the church.

Two former members of the church in America describe in detail how they were pressured to have abortions when they fell pregnant to their husbands within the Sea Organisation.

Both women say that they wanted to give birth to the children, but were told not to do so.

Mr Davis tells Four Corners: "Sea Org members do not have children. If someone is a member of the Sea Organisation and they wish to have a child, they would need to do so outside of the Sea Org," but he denies that the church has any policy of coercing women into having abortions.

However, one of the women reporter Quentin McDermott interviewed has composed a list of 40 other women who - she says - say that they too were "coerced" into having abortions in America.

Tonight's Four Corners presents evidence that women inside the Sea Org in Australia have also been put under pressure to have abortions when they fall pregnant.

This week Independent Senator Nick Xenophon is expected to move that an inquiry take place into "the abuses against Australians that have taken place within the organisation of Scientology".

Senator Xenophon told the Senate last November: "Scientology is not a religious organisation. It is a criminal organisation that hides behind its so-called religious beliefs."

Prime Minister Kevin Rudd commented at the time: "Many people in Australia have real concerns about Scientology. I share some of those concerns."