By Sarah Marsh

BERLIN (Reuters) - Germany's opposition conservatives are expected to win another term in the Hesse and Bavaria state elections on Sunday, seen dealing a blow to Chancellor Olaf Scholz's center-left coalition and attesting to the rise of the far-right.

Worries about national issues like migration, the cost of the green transition and stagnation in Europe's largest economy have overshadowed the campaigns in both states, home together to around 20 million people - more than many European countries.

So too has frustration with infighting in Scholz's heterogeneous three-way coalition of Social Democrats (SPD), the Greens and pro-business Free Democrats (FDP) mid-way through its term.

"The coalition is suffering the mid-term blues and must reckon with losses," said Stefan Marschall, political scientist at the University of Duesseldorf. "The FDP in particular must reckon with falling out of both state parliaments which could bring greater tensions into the coalition.

"The conservatives are benefiting from this dissatisfaction with the government."

So too is the far-right Alternative for Germany (AfD) which has surged to second place in nationwide polls and is expected to gain ground on the last elections in 2018 in both states.

The latest polls in Bavaria put the Christian Social Union (CSU), the Bavarian sister party of the Christian Democrats (CDU), on 36-37%, which would be its lowest result in decades but still allow it to continue ruling the state.

More striking is the fact the populist Free Voters (FW) party, which governs Bavaria in coalition with the CSU, has seen a bump in poll support of several percentage points to 15% since being swept up in an anti-semitic scandal.

That is also well above the 11.6% it scored at the last elections in 2018.

The Greens are seen polling in second place in Bavaria on 16%, followed by the FW and the AfD on 14%, the SPD on 9% and the FDP on 3% - well below the 5% threshold needed to enter parliament.

In Hesse, the CDU are polling at 32% - up from the 27% they won at the last election in 2018 - followed by the SPD and Greens tying at 17%, the AfD on 16% and the FDP on 5%.

Such results would deal a blow to Interior Minister Nancy Faeser, the SPD's lead candidate in the state, who has faced criticism for her handling of growing irregular migration which has burdened local authorities.

Approval of Scholz's government remains at its lowest level since taking office in December 2021, according to the ARD-Deutschland Trend survey, with four out of five Germans dissatisfied with its work.