Former Greek minister Yiannos Papantoniou and his wife Stavroula Kourakou were incarcerated in Korydallos prison at a Piraeus port suburb on Wednesday following a prosecutor's decision, Greek national news agency AMNA reported.

Greek judicial authorities ordered that the couple be remanded in custody following their testimony on charges of money laundering.

The 69-year-old former official and his spouse denied charges of having laundered 2.8 million euros (3.19 million U.S. dollars) in kickbacks for a contract to upgrade six Greek navy frigates, according to judicial sources.

The contract was signed in 2003 when Papantoniou was at the helm of the defense ministry (2001-2003). Earlier he had also served as Economy and Finance minister in a socialist government.

In November 2014 the former minister was convicted by an Athens court of failing to declare 1.2 million euros found in a Swiss bank account held under his wife's name as part of an investigation launched regarding 2,000 Greeks who were major depositors in an HSBC branch in Switzerland.

The Greek list was part of a wider database leaked by an HSBC former employee to French authorities and was handed to Greek authorities from International Monetary Fund managing director Christine Lagarde, when she serving as France's finance minister in 2010.

For this case Papantoniou has filed an appeal to the European court of human rights against the Greek courts' ruling.

For a similar case on charges of receiving kickbacks and money laundering former defense minister Akis Tsochatzopoulos (1996-2001) was sentenced to 20 years in prison in 2016.

Tsochatzopoulos, 79, also a socialist, was released this summer due to ill health.

He was the highest former official to be convicted for corruption in Greece in several decades.

His wife, Vicky Stamati, who was also sentenced to 12 years in prison for the same case, was released in 2015 for health issues. (1 euro=1.14 U.S. dollars)