Nigeria: Where religion is big busines

One of the key messages these churches preach is that financial prosperity is a sign of God's favour.

As they have grown in popularity since the early 1990s, so has the wealth of their pastors.

Many of them own luxury cars, while a few even travel in their own private jets.

Mr Okotie argues that prosperity is an integral part of the gospel.

"It is written about Jesus, specifically, that he became poor so that the believer might become rich, because he recognised that poverty is not part of God's plan for man," he says.

The head of another church, David Oyedepo, is said to have a net worth of up to $150m.

His Living Faith Church - also known as Winners Chapel - hosts three services every Sunday in Lagos, in a 50,000-seat church, and has branches in Ghana, Kenya, Liberia, Ivory Coast, South Africa, Gambia, the UK and the US.

He also runs a publishing house, a university and a secondary school.

But it is another popular church, the Redeemed Christian Church of God (RCCG), which leads the pack, having thousands of outposts around the world - including at least 2,000 in Nigeria, and close to 400 in the UK.

The churches earn money from sales of books written by the pastors, and CDs and DVDs of the sermons, but the bulk of their revenue is said to come from donations from the congregation.

Some people find the idea of churches amassing such wealth problematic.

Local press reports that David Oyedepo was selling two of his church's private jets led to accusations of extravagance, although his church insists the planes were used by senior staff for work.

Nigeria's anti-corruption agency, the Economic and Financial Crimes Commission, recently said that churches needed to find out the sources of larger donations, to ensure the money was legitimately earned, if the country's fight against corruption was to be successful.

The head of the commission, Farida Waziri, insists that the church's prosperity "must come legitimately".

"A responsible pastor should know where the tithe of his worshipper is coming from," she says. "How and where did you make the money that you are bringing in as tithe? It is not enough for your member to bring in a huge amount and you say 'God bless you.'"

Some Nigerians want to see a clearer line drawn between the churches' possessions and those of their pastors.

Chris Okotie says his personal wealth comes from his previous career as a musician and from his other business ventures.

But critics accuse the pastors of taking advantage of needy congregations, by telling them to give money to the church in exchange for financial and spiritual rewards from God.

These churches are "big-time businesses being managed by entrepreneurs", says Leo Igwe of the Nigeria Humanist Movement.

"It's as a result of poverty, social and economic collapse problems. Nigerians have become desperate, and gullible, and these churches service this market."

"No! No! No!" responds Prince Okpaku, a member of Chris Okotie's congregation.

"It is God that has brought us thus far, and He's not even interested in offerings. The offering is strictly for benevolence assistance," he says.

Still, the churches continue to expand and, as more branches open around the world, they are proving to be among Nigeria's most successful exports.