Papua New Guinea police say the arrest of the lawyer Paul Paraka is only the beginning of Task Force Sweep.
Mr Paraka faces 18 charges of fraud, including receiving payments from Government departments to the order of 25 million US dollars.
He strongly denies the charges and has spent months in the courts trying to prevent his arrest, saying it is motivated by jealousy.
A Detective Superintendent and the Director of National Fraud and Anti-Corruption, Matthew Damaru, says Mr Paraka was granted bail of 17,500 US dollars after a long interview with police.
He says two other lawyers were arrested, and there are high-profile people in the Government who are key suspects.
"A case of money laundering where funds earmarked for Paraka Lawyers were channelled through these other law firms, forwarding the funds to Paul Paraka and keeping a commission for themselves. There are people in the Government involved, people of high standing in the Government and in some of the agencies, the private sector as well. We will investigate, and those who are involved will be prosecuted as well."
Superintendent Matthew Damaru.