Most countries' leaders avoid high-level public interactions with Taiwan and its president, not wishing to provoke China, the world's second largest economy.
In 2016, U.S. President-elect Donald Trump spoke by telephone with Tsai shortly after winning the election, setting off a storm of protest from Beijing.
Pavel's spokeswoman said he and Tsai were expected to speak at 1000 GMT.
Taiwan's presidential office did not immediately respond to a request for comment, but said on Sunday that Tsai had offered her congratulations to Pavel on his victory.
Pavel, a former army chief and high NATO official who won the Czech presidential election on Saturday, will take office in early March when he will replace current head of state Milos Zeman, who has been known for his pro-Beijing stance.
The Czech Republic, like most countries, has no official diplomatic relations with Chinese-claimed Taiwan, but the two sides have moved closer together as Taipei seeks new friends in Eastern and Central Europe.
Pavel has strongly backed Western support for Ukraine in its defence against Russia's invasion.
Taipei has sought to bolster its relations with European countries by stressing their shared values of freedom and democracy, especially as Beijing ratchets up military threats to try and force Taiwan to accept Chinese sovereignty.
In 2020, the head of the Czech Senate visited Taiwan and declared himself to be Taiwanese in a speech at Taiwan's parliament, channelling the late U.S. President John F. Kennedy's defiance of communism in Berlin in 1963.
(Reporting by Robert Muller and Jason Hovet; Additional reporting by Ben Blanchard and Yimou Lee in Taipei; editing by Ed Osmond and Gareth Jones)
