An evangelical church's charitable arm has rejected claims it has not been transparent in spending a Federal Government grant to help Indigenous business.

Indigenous development grants to Hillsong's benevolent arm have gone almost entirely to employing and providing offices for church staff, with only a trickle reaching Aborigines.

The ministry established by Brian and Bobbie Houston, senior pastors of the dynamic Hillsong Church, has become a $1 million-plus business.

When Brian Houston established a tiny house of worship in Sydney 20 years ago, he never dreamed he would be at the helm of Australia's largest indpendent church. He tells Australian Story what the experience has been like.

CAROLINE JONES, PRESENTER: Hello, I'm Caroline Jones. Tonight, a revealing look at the family behind the Hillsong phenomenon. When Brian and Bobbie Houston established their own tiny house of worship 20 years ago, they didn't dream they'd end up at the helm of the biggest independent church in Australia. While Hillsong revels in chart-topping CDs and the beaming approval of some prominent politicians, it does divide observers. Some admire the church's material and spiritual success. Others suspect a political agenda and worry about Hillsong's financial arrangements. Through it all the Houstons have avoided personal media scrutiny, but tonight, for the first time, they've allowed cameras into both their church and their private life so people can judge for themselves. This is their story.

MAXINE McKEW: Earlier this week the Treasurer, Peter Costello, attended a religious gathering of more than 16,000 people, underscoring Government support for an increasingly important part of the electorate - the Hills District of Sydney.