The Church of Scientology's plan to convert a warehouse in Rivervale into a $6 million purpose-built church is the next phase of a national push that has so far involved the purchase of $58 million of property in Sydney and Melbourne.

And it claims that as many as 30,000 West Australians have expressed an interest in the religion through visits to their website.

The site of the proposed new Perth Church of Scientology building in Rivervale. Credit:James Mooney

People practicing scientology include lawyers, teachers, accountants, doctors, fine artists, writers and beauticians - and many are self-employed business owners.

The church spent $21 million to buy and refurbish the Sister's of Mercy College in Ascot Vale, Melbourne, that reopened in 2011. Late last year it spent $37 million to snap up the 3.5 hectare site of the former National Acoustic Laboratory in the leafy Sydney north shore suburb of Chatswood West. It will become the new national headquarters of the church.