Berlin (AFP) - Ukraine's Prime Minister Arseniy Yatsenyuk hit out Friday against President Petro Poroshenko and his camp, accusing them of undermining key reforms that are badly needed to overcome the ex-Soviet state's economic malaise.

In an interview with the Frankfurter Allgemeine Zeitung daily, Yatsenyuk also warned Poroshenko that if he were forced out from government, it could jeopardise the delivery of a massive IMF-led rescue package.

"I say to the president: If you don't want me anymore, then you have to form a new government. You won't be able to do that and so you'll have to call early elections," warned Yatsenyuk.

"In the meantime, there will be no one who would be able to seal a crucial credit agreement with the International Monetary Fund," said the 41-year-old former banker.

Yatsenyuk has endeared himself to the West by pushing through belt-tightening measures but voters, fed up with the harsh austerity, also accuse him of backing the interests of billionaires and not the common people.

Yatsenyuk, however, shrugged off the criticism, saying he had "pay a high price" with the unpopular reforms aimed at "saving the national budget".

"For me, it's more important to protect our unity than to win a few popularity points," he told the German daily.

He took aim instead at Poroshenko's bloc, saying the "majority of them had supported a no-confidence vote (against Yatsenyuk), and with that they tried to block our reforms".

Ukraine's economy shrank by about 10 percent last year while annual inflation soared to more than 43 percent even with the Western assistance in place.

The political infighting in Ukraine has threatened to put key IMF assistance on hold.

IMF chief Christine Lagarde warned in early February that it was "hard to see" how the bailout could continue without Ukraine pushing through the economic restructuring and anti-corruption measures it had signed on to when the package was agreed.