Retired NATO general Petr Pavel looks a clear favourite to beat billionaire former prime minister Andrej Babis in the Czech presidential election run-off on Friday and Saturday.

The victor will replace Milos Zeman, an outspoken and divisive politician who nursed close ties with Moscow before making a U-turn when Russia invaded Ukraine nearly a year ago.

Former paratrooper Pavel topped final opinion polls with 58-59 percent support against 41-42 percent for Babis.

Eight candidates stood in the first round vote when Pavel edged Babis with 35.4 percent against 35, and with right and centre backing he has since wooed the voters of several of those also-rans.

Babis can rely on stable support from voters of his centre-left populist ANO movement, but he appears unlikely to win over a significant number of new votes.

He also even annoyed some with rather chaotic diatribes in debates, which led Masaryk University analyst Otto Eibl to tell AFP he was "rhetorically hard to figure out".

The new head of state will face record inflation in the central European EU and NATO member of 10.5 million people.

While the role is largely ceremonial, the president names the government, picks the central bank governor and constitutional judges, and serves as top commander of the armed forces.

"Quite frankly, if the (opinion) polls are well conducted, I think it will be hard for Babis to come back," Palacky University analyst Tomas Lebeda told AFP.

"I expect Petr Pavel to win," he added.

Decorated war hero

The 61-year-old Pavel was decorated as a hero of the Serbo-Croatian war in which he helped free French troops from a war zone.

He went on to become the chief of the Czech general staff and chair of NATO's military committee.

Babis, 68, who owns the Agrofert food, chemicals and media group, is the fifth wealthiest person in the Czech Republic, according to Forbes magazine.

He served as prime minister from 2017 until 2021, constantly battling questions about his dual role as politician and entrepreneur.

Both Pavel and Babis were members of the Communist Party in the 1980s when Czechoslovakia was ruled by Moscow-steered communists.

Pavel won the endorsement of several parties in the governing centre-right coalition of Prime Minister Petr Fiala, while Babis secured backing from long-time ally Zeman, whose last term expires in March.

Babis also raised controversy at the tail end of the campaign by saying he would not send troops if fellow NATO members Poland or the Baltic states were attacked.

He later walked back the comments, but not before he had garnered criticism from all four countries.

Independent political analyst Jan Kubacek said he believed the election would not bring a change in foreign policy, no matter the victor.

"The Czech Republic will stay pro-Western, it will retain its strategic relationship to the EU and NATO, it will stay on Ukraine's side," he told AFP.

Polling stations open at two pm (1300 GMT) on Friday and close at 10 pm before reopening at eight am and closing at two pm on Saturday.

The results are expected shortly after polls close.