The Finance Ministry issued a statement on Monday saying that three MPs are being checked in connection to money that was transferred abroad between 2009 to 2012.
Reports had suggested that three New Democracy MPs were under the spotlight for transferring more than 1 million euros each to foreign bank accounts.
The ministry did not refer to the amounts involved but said the three lawmakers in question are Vassilis Kikilias of New Democracy, Maria Repousi of Democratic Left and Vassilis Kapernaros of the Independent Greeks.
Kikilias had earlier issued a statement insisting he did not have deposits abroad. Kapernaros also denied having any savings outside Greece.
The Finance Ministry said the conservative lawmaker said that he submitted paperwork to his local tax office following a request last April. All three parliamentarians remain under investigation, the ministry added.
Earlier, SYRIZA had asked for a parliamentary committee to look into the matter.