Ukraine's reform-minded economy minister Aivaras Abromavicius announced on Wednesday that he was quitting his post because of "actions directed at paralyzing our work," state media reported.
Senior officials were blocking key reforms that the cash-strapped government needs to implement in order to secure foreign financial aid, he said.
Lithuanian-born Abromavicius was appointed in 2014 after Ukraine ousted its former pro-Russian president amid mass protests calling for closer ties with the West.
He singled out Igor Kononenko, a close ally of President Petro Poroshenko, as one of the officials working "behind my back," state news agency Ukrinform reported.
Abromavicius called for Ukraine's parliament to approve his resignation as soon as Thursday.
Poroshenko has become significantly unpopular as Ukrainians increasingly believe he has failed to fulfil his campaign promises, US-based pollster Gallup said in December.
His approval rating among the Ukrainian people is a meagre 17 per cent, well below the 28 per cent that his pro-Russian predecessor Viktor Yanukovych had before being ousted, the pollster said in a statement on its website.
"Poroshenko's low approval rating largely reflects Ukrainians' disenchantment with their leadership, which many feel has failed to deliver on what protesters demanded when they took to the streets two years ago," the pollster said.