Mfonobong Nsehe, who blogs for Forbes business magazine, says pastors own businesses from hotels to fast-food chains.
"Preaching is big business. It's almost as profitable as the oil business," he said.
The joint wealth of five pastors was at least $200m (£121m), he said.
Bishop Oyedepo owned a publishing company, university, an elite private school, four jets and homes in London and the United States, according to Mr Nsehe.
The Nigerian blogger said Bishop Oyedepo was followed on the rich list by Pastor Chris Oyakhilome of the Believers' Loveworld Ministries. He was worth between $30 and $50m.
These pastors are flamboyant. You see them with private jets and expensive cars," Mfonobong Nshe Nigerian blogger
"Oyakhilome's diversified interests include newspapers, magazines, a local television station, a record label, satellite TV, hotels and extensive real estate," Mr Nsehe said.
He said three of the other richest pastors were:
- Temitope Joshua Matthew of the Synagogue Church Of All Nations (worth between $10m and $15m);
- Matthew Ashimolowo of Kingsway International Christian Centre (worth between $6 million and $10 million) and
- Chris Okotie of the Household of God Church (worth between $3 million and $10 million).
Mr Nsehe said representatives of all the clergymen, except Pastor Ashimolowo, confirmed ownership of the assets he had listed on his blog.
"These pastors are flamboyant. You see them with private jets and expensive cars. This extravagance sends out the wrong message to their followers," he told the BBC's Network Africa programme.
He said the pastors acquired their wealth from various sources, including their congregations.
"We have Nigerians who are desperate, looking for solutions to their problems. They go to church for salvation, redemption and healing and pastors sometimes take advantage of them," Mr Nsehe said.
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