A world leading expert and critic of Scientology has revealed the secretive organisation’s plans for Australia.

Tony Ortega, who is currently in Sydney to launch his latest book, said a new $50m Super Centre on the north shore will become the key base for Scientologists in the Southern Hemisphere.

However, he has claimed it’s just an expensive front for dwindling numbers.

For 20 years, New York journalist Ortega has been revealing abuses inside Scientology.

View photos For 20 years Tony Ortega has been revealing what goes on inside Scientology. More

“They have a lot of money.. It's the combination of millionaires donating money, paying their workers pennies an hour and not having to pay taxes,” he said.

The church has just purchased a $40m complex in Chatswood and plan to spend millions renovating it to look similar to their Super Powers building in Florida.

"Australia was always really important to L. Rob Hubbard and he really saw it as being a major place for scientology,” he told 7 News.

View photos

Despite this Ortega believed the group was struggling to draw the crowds it once did.

“On certain continents Scientology has this thing called ‘the advanced org’ where Scientologists can only take the highest level courses and for some reason they think Australia has enough demand to put one here when that's just not the case,” he said.

“They took over this $40m facility but they had to submit papers about it about what they're going to do with it and they admitted their daily foot traffic is going to be 30-40 people.

“What other organisation would spend $40m for a facility that is going to serve so few people? The answer is all this acquisition of buildings is about public relations, trying to convince people they're expanding when they aren't”.

The church has denied it's losing members, calling Ortega ‘a parasite’ and ‘a religious bigot’.

Independent Senator Nick Xenophon worried about Scientology’s focus on Australia.

“This has got nothing to do with religious freedom, it's got everything to do with the outrageous behaviour of the Church of Scientology and the way that they have destroyed people's lives,” he said.

Ortega’s new book details the story of one of the first writers to expose the church, Paulette Cooper.

“This is probably the worst example of Scientology deciding someone is an enemy and then setting out to destroy their life,” he said.

Story continues