Onazi, 21, was caught on camera - planted by English newspaper The Sun - meeting with player agent Henry Chukwuma Okoroji and an alleged match-fixer, with the player reportedly present to benefit the agent's chances of securing a fix.
The Lazio man said he turned down the advance to organise a yellow card, or a penalty, after discovering why the meeting was set up - only attending as he was led to believe it was an 'endorsement proposition'.
"My attention has been drawn to a publication relating to issues about match-fixing," Onazi posted on Twitter.
"First, let me state unequivocally that I have no link whatsoever to any individual or group with ties to the corrupt issues of match-fixing.
"A certain Mr Okoroji was mentioned in the publication. My previous contact with Mr Okoroji was based on the fact that we are both Nigerians. As a matter of fact, I am surprised to learn that Mr Okoroji is a FIFA licensed agent.
"On the day of this meeting, he had earlier told me that his associates had an endorsement proposition for my consideration.
"I duly informed my friend who manages my affairs.
"When I got to the meeting, I found out it was all about fixing matches. I told them a resounding NO and left.
"Interestingly, this is the same version sated (sic) in the publication."
Nigeria are already under investigation for an alleged fix in their friendly with Scotland in London, as they prepare for their World Cup campaign in Group F alongside Iran, Bosnia-Herzegovina and Argentina.
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