Ukraine has handed foreigners, including a US citizen, top posts in a new reformist government it says is aimed at rooting out endemic corruption.

President Petro Poroshenko told a marathon parliament hearing on Tuesday that Ukraine has to learn from "foreign experience" as it tries to climb out of bankruptcy that many blame on decades of political gridlock and graft.

He then signed decrees awarding Ukrainian citizenship to US national Natalie Jaresko - the head of a private equity fund whom parliament confirmed as finance minister - and Lithuanian investment banker and new economy chief Aivaras Abromavicius.

Lawmakers also confirmed the New York-based Georgian former health minister Alexander Kvitashvili will now serve the same role in Ukraine.

After past accusations of US meddling in Ukrainian politics, State Department deputy spokeswoman Marie Harf denied that Washington had any hand in the choice of an American as finance minister.

"This is a choice for the Ukrainian people and their elected representatives. This is their decision," Ms Harf told reporters.