Ukraine's parliament approved presidential ally Volodymyr Groysman for the post of prime minister on Thursday in the biggest political shakeup since a 2014 uprising brought in a pro-Western leadership.

A new Groysman-led government could end months of political infighting that has stalled efforts to tackle graft and delayed billions of dollars in foreign loans.

But reformists have expressed concern over the departure of experienced Western-backed technocrats from the cabinet.

Speaking ahead of the vote, Groysman said his government was committed to tackling graft and strengthening ties with the European Union.

"I understand the threats that face us. In particular I would like to highlight three threats - corruption, ineffective governance and populism, which do not pose less of a threat than the enemy in eastern Ukraine," he said, referring to a pro-Russian separatist rising.

"I will show you what leading a country really means," he added.

Groysman's nomination was backed by 257 deputies, comfortably over the minimum 226 needed.

The rebooted cabinet under Groysman, an ally of President Petro Poroshenko, appears to strengthen the president's influence on the economic side of policymaking.

Oleksandr Danylyuk, 40, who is set to become finance minister, is the deputy head of Poroshenko's administration, while the economy minister and first deputy prime minister positions will be given to Stepan Kubiv, who is currently the president's representative in parliament.

They replace U.S-born Finance Minister Natalia Yaresko, praised by Washington for her handling of Ukraine's debt crisis, and former economy minister Aivaras Abromavicius, who spearheaded a drive to privatize graft-ridden state firms, but resigned in protest over corruption in February.

Addressing parliament, Poroshenko said the new government must honor reform commitments made under a $17.5 billion bailout program from the International Monetary Fund, which has held back payments since October due to the political crisis.

"I stress the imperative and inviolable necessity of continuing cooperation with the IMF and other international lenders," he said.