Kazakhstan is suing New York financier Daniel Chapman and Argentem Creek Partners where he serves as CEO, alleging he conspired with Moldovan businessman Anatolie Stati to fraudulently secure an arbitration award of over $0.5bn against the oil-rich country, according to documents filed with a New York court.

At stake is a $0.5bn award won by the Moldovan businessman, who claims his investments in Kazakhstan were illegally nationalised.

Kazakhstan has, in turn, accused Stati of defrauding both the former Soviet republic and the Swedish arbitrators who initially ruled in his favour in 2013, charges the Moldovan investor and his companies deny.

Further upping the stakes, in a lawsuit filed in the Supreme Court of the State of New York, the government in Nur-Sultan accused Chapman and his companies of “conspiring with, and aiding and abetting, a fraudulent scheme” led by Stati.

Kazakhstan is seeking a jury trial and pursuing relief permitted by law, including compensatory and punitive damages.

“This includes any damages arising from the legal proceedings initiated by or involving the Statis in which the fraudulent scheme was perpetuated,” Justice Minister Marat Beketayev said in a statement.

The Amsterdam Court of Appeal published its judgment in the case of Anatolie Stati et al v the Republic of Kazakhstan in mid-July this year, rejecting Kazakhstan’s appeal, therefore affirming recognition on Dutch soil of the $543mn arbitral award issued by a Stockholm-seated arbitral tribunal in December 2013.

The Dutch court ruling is the latest development in the Stati parties' long-running international battle to enforce the award for Kazakhstan's violations of the investor protection provisions of the Energy Charter Treaty. Back in 2013, a Sweden based arbitration tribunal found that Kazakhstan had violated international law by failing to treat the Stati parties' investments in Kazakhstan fairly and equitably.

Stati, the CEO and sole shareholder of Ascom Group, one of the award creditors, said that “the judgment also paves the way for the foreclosure of the attached shares in KMG Kashagan B.V.”.