KIEV (REUTERS) - Ukrainian police have seized 42kg of gold and US$4.8 million (S$6.1 million) in cash during a search of the apartments of Ukraine's former Energy Minister Eduard Stavytsky, Interior Minister Arsen Avakov said on Saturday.

Avakov said the searches had been conducted in connection with a corruption investigation in the energy sector.

"It blew my mind when I received a report on the results this morning. How much would one have to steal, to have such a 'trifle' at home as pocket money," Avakov said in a post on Facebook.

Stavytsky's career blossomed under the presidency of ousted Viktor Yanukovych and was appointed energy minister in December 2012.

Ukrainian media describe Stavytsky as a member of Yanukovych's inner circle. He could not be reached for comment.

Ukrainian police on Friday detained another energy official - the chief executive of state energy company Naftogaz, Yevhen Bakulin, as part of the investigation into corruption that it says may have cost the Ukrainian state about US$4 billion.

Naftogaz is responsible for the import and distribution of Russian natural gas in Ukraine. It also holds a monopoly on the shipment of gas from Russia's Gazprom via Ukraine to Europe.