World Bank figures reveal that Nigerian migrants send $653 million (€500) back home from Ireland each year.
In 2011, figures show $602 million (€468m) in 'remittances' was sent from Ireland to Nigeria, an average of more than €26,000 for each of the 17,642 Nigerian nationals in Ireland, including children.
This is far more than was sent home by Poles from Ireland, who sent $224 million (€174m), even though there are more than 122,000 Polish people in the country.
Money sent from Ireland by foreign migrants is three times higher than money being sent home to Ireland from Irish living abroad, with figures showing that Irish abroad sent more than $750 million back home in 2011.
The same year, foreign migrants working in Ireland sent $2.4 billion home.
The Irish Independent reports that the issue will be raised during a Dail debate this week on the Criminal Justice (Money Laundering and Terrorist Financing) (Amendment) being rushed through before next month's G8 summit in Enniskillen, Co Fermanagh.
Niall Collins, Fianna Fail's justice spokesman, said: "It raises a number of questions. There may be legitimate and valid reason for the extremely large amounts of money being sent from Ireland to Nigeria, compared with the amounts sent by other nationalities.
"On the face of it, it has to be questioned. I will be asking the minister to investigate and find out why."
According to the Independent, the largest amount of money leaving Ireland in 2011 was to Britain, at over €529m, followed by Nigeria (€468m) and Poland at (€174m).
2011 World Bank figures show that remittances to poorer countries totaled €289bn ($377bn), with total remittances worldwide estimated at €390bn ($509bn).