Slovak Prime Minister Igor Matovic announced on Sunday that he intended to resign after coming under intense pressure over the coronavirus crisis but said he wanted to stay in the government as finance minister.

Matovic, whose decision to buy Russian vaccines has been hugely controversial, did not specify when he would resign and said he wanted the current finance minister, Eduard Heger, to replace him.

"We will exchange our posts with minister of finance, Eduard Heger... He is a good man and all of us can trust him," Matovic told reporters in the latest twist in a weeks-long crisis triggered by the pandemic.

Heger, 44, is a former businessman and also worked as a consultant for the Ministry of Defence.

He became minister of finance in March 2020 when his and Matovic's OLaNO party won a general election.

Heger is currently also the acting health minister.

Relatively spared at the start of the pandemic, Slovakia's healthcare system has struggled during the third wave of the virus and the country has one of the highest Covid death rates in the world per capita.

Six ministers, including the health minister, have left the 16-member cabinet and one party has said it is leaving the four-party governing coalition unless Matovic quits the government entirely.

Matovic, a former businessman in the publishing industry, came to power last year after beating the governing populists on an anti-corruption platform.

While supporters view him as a maverick with a knack for self-promotion, critics accuse Matovic of being an unpredictable, attention-seeking control freak.

During the pandemic in Slovakia, a eurozone country of 5.4 million people, Matovic's critics have accused him of poor communication and political missteps.

But his decision to buy Sputnik V vaccines has proved particularly divisive, with the former foreign minister Ivan Korcok calling the jabs "a hybrid war tool".

Opinion polls from March 21 suggested that more than 80 percent of Slovaks agreed that Matovic should resign.

President Zuzana Caputova last week joined calls for Matovic to resign, saying it was "essential" that he step down to end the political crisis.

Matovic would have to formally announce his resignation before Caputova can ask Heger to form a government.

Heger would then need to build consensus behind his candidacy within the coalition and then seek the approval of parliament in a confidence vote.