Scientologists around the world are looking forward to the weekend opening of their sect's very own 'Vatican'.

Fifteen years in construction, at a cost of $80m, the Super Power Building will open soon on Florida's Gulf Coast.

According to the Times, leaked plans of the interior design include an office for Scientology's founder L Ron Hubbard, for his sole use, even though he died over 26 years ago.

The Super Power Building is seven storeys high, with an enormous footprint of 377,000 sq ft.

"Super Power is the answer to a sick, a dying and dead society. With it we literally revive the dead," wrote science fiction writer turned spritual guru Hubbard.

To mark the opening of the Scientology HQ, a three-day celebration is planned underneath the awning of a giant tent.

It's not yet been confirmed whether Scientology stalwarts Tom Cruise and John Travolta will be there.

A virtual online tour of the former Fort Harrison Hotel, described as a religious retreat, reveals a luxury resort with three restaurants, a ballroom, swimming pool, garden pavilion, and 220 bedrooms and suites for guests.

The Church of Scientology is facing a federal lawsuit in Tampa, Florida, brought by two former church members. They say they gave $340,000 to the Super Power project.

According to the Times, the lawsuit alleges that completion of the building was stalled deliberately over the years to pressurise other members to continue funding the project.

The church "improperly utilised the contributions and deposits to, among other things, engage ranks of professionals to stifle inquiries into the church's activities and finances, to intimidate members and ex-members, to finance the lavish lifestyle of Miscavige and to fill the coffers of the church or its subsidiary/affiliated organisations," says the lawsuit, brought by Californian philanthropists Luis and Maria Garcia.

Scientologists have denied the accusations, saying they are "blatantly false".

A judge has yet to rule on whether the case can proceed.

If the lawsuit does make it to the courts, Ted Babbit, the Garcias' lawyer, intends to subpoena Miscavige, the church's leader for 30 years.

"I've taken on some of the biggest corporations in America," said Babbit. "I'm not afraid of taking on the Church of Scientology."