More than $1.3 million and 50 credit cards were seized, the ministry said, adding that police suspected the gang had laundered "huge quantities of money derived mainly from illegal casinos in Russia".
The gangs are suspected of laundering money from criminal activities in the former Soviet Union by investing it in real estate, restaurants, bars, luxury cars and other assets in Spain, the ministry said.
One alleged crime boss from Georgia, Zahar Knyazevich Kalashov, was arrested in Dubai in May and extradited to Spain the following month.
Dubai security officials describe Kalashov as one of the most dangerous and important bosses of Russian and Georgian crime organisations.
The statement said tax officials were working to determine the exact amount of the money involved in the gang's alleged laundering activity.