According to The Straits Times married couple Singaporean Lim Ai Wah and her American husband Thomas Doehrman laundered $US3.6 million, which had been meant to set up community colleges in PNG.
Media reports say the pair deposited $US784,000 ($A1.04 million) in a Singapore bank account belonging to Somare.
The pair were each found guilty of one count of falsifying accounts and five charges of transferring the benefits of criminal conduct. Wah was sentenced to five years' jail while Doehrman received five years and 10 months.
According to reports Somare said in a statement that he had never received inducements or bribes at any time in his political career.
"A court case has found two persons in Singapore guilty of money laundering offences and subsequently names me as a recipient of some funds," he said.
"I have taken steps to get clarification and legal advice on this matter, but I would like to state from the outset that at no time in my political career have I received inducements or bribes.
"At first glance these charges say otherwise. Therefore, during the next few days I will consult with my family and legal counsel and consider how to address this matter."
The Straits Times reports Somare's Singaporean bank account has been frozen.