Helsinki — If Finland's politics seem baffling to a Western observer, they must be even more frustrating to the Kremlin. As Finnish politicians maneuver to succeed Urho Kekkonen, president for 25 years until his retirement in October, Moscow's many unsubtle hints as to who it would like to see govern Finland for the next six years have fallen on stony ground.
The Soviet Union's most notable failure so far has been its inability to influence the choice of candidate by Kekkonen's own Center Party. A ''commentary'' in Pravda suggested that the best choice would be Ahti Karjalainen, a former prime minister and, more important from the Russian point of view, co-chairman of the Finnish-Soviet Trade Commission.
It flopped spectacularly when the party opted instead for the flamboyant Johannes Virolainen, speaker of parliament.
Virolainen's victory was all the more remarkable when the grass roots of the party rejected their own leadership's recommendation of Karjalainen and contemptuously ignored ''evidence'' of Virolainen's ''unsuitability'' revealed in letters from the ailing Kekkonen. This ''unsuitability'' was based on Virolainen's attitude to the Soviet Union, said to be less sympathetic than that of Karjalainen.
Further hints from the Kremlin that Mauno Koivisto, Social Democratic prime minister, would also be unacceptable have done nothing to diminish his popularity among a wide range of Finnish voters. The latest public opinion poll gives him a commanding lead, with 60 percent favoring him as the next president.
Although he is unlikely to change Finland's policy of not offending ''the bear next door,'' Koivisto is disliked in Moscow for his devil-may-care forthrightness. Remarks like, ''All I know about the economy is that it will be worse than last year,'' may make Finns laugh but they strike an odd note for Soviet ears.
The Finnish Communist Party itself is no longer on speaking terms with Moscow as a result of a joke told by Arvo Kemppainen, a member of the party hierarchy, at an informal reception in the Finnish Embassy in Moscow. It poked fun at President Brezhnev's age. The joke was innocent enough by Western standards but the Russians did not laugh.
When Kemppainen was later refused a visa to return to Moscow, it was the signal for bitter infighting between extremists and moderates in the Finnish Communist Party. The moderate wing has so far won the day with the choice of Kalevi Kivisto as presidential candidate.
If Kivisto is moderate by Finnish communist standards, the conservative National Coalition Party's choice for president, Harri Holkeri, is almost a left-winger as seen through Western eyes. But he would be regarded as a threat to continued good relations by Moscow, should his party enter the government in parliamentary elections following the swearing in of the new president.
While unlikely, this could happen as a result of the peculiarities of the Finnish system, which on Jan. 17 and 18 will see the electorate choosing an electoral college of 301 members. This body then chooses the president; the process involves much political horse-trading before the final vote is taken on Jan. 26.
The conservatives might be able to persuade Koivisto to allow them into the government in exchange for support for his presidency. And Koivisto might just be cheeky enough to agree.
More likely, however, Finland will continue with a left-of-center coalition leadership along much the same lines as those laid down during the Kekkonen era.