German Chancellor Angela Merkel's Bavarian allies have scored a resounding win in a state vote, provisional results show.

Sunday's results, from Germany's second-most populous region, point to a strong likelihood that Merkel, leader of the Christian Democrats (CDU), will clinch a third term in next Sunday's parliamentary elections.

However, the pro-business Free Democrats (FDP), junior partners in Bavaria and under Merkel in Berlin, got just three percent, dropping out of the regional parliament.

The results raise the prospect of a close finish to see whether she can continue her centre-right government or will have to form a "grand coalition" with her traditional rivals, the Social Democrats.

The conservative ruling Christian Social Union (CSU) captured an absolute majority of seats in the Bavarian parliament with 48.8 percent of the votes, according to provisional results from 73 of the 90 polling districts.

Its strong victory means it can drop the FDP and govern alone.

"One Bavarian in two voted for us," Horst Seehofer, incumbent state premier, told jubilant supporters.

"That is a huge vote of confidence."

Hard campaign

Merkel campaigned hard in the state's world-famous beer tents, pointing out that a big win in Bavaria would lend momentum to her bid for another term at the helm of Europe's top economic power.

She did not make any immediate comment on the results but was expected to give her views on Monday.

National polls give Merkel's conservatives a lead of around 14 points over the main opposition Social Democrats (SPD), who scored just under 20 percent of the vote in Bavaria, historically a conservative state, according to the early results.

The 19.9 percent recorded was not far above the SPD's historic low showing of 18.6 percent in 2008.

However, Merkel's chief election rival, Peer Steinbrueck of the SPD, took heart from the FDP's setback.

"This is the 13th state election in a row in which the centre-right love match failed to win," he told public television.

"There is a good chance that this will also happen on the federal level in a week's time."

The ecologist Greens turned in a dismal eight percent, in keeping with a downward trend on the national level.

The CSU has ruled Bavaria uninterrupted for 56 years with a winning strategy of "laptops and lederhosen" - high-tech business savvy coupled with proud tradition.

Absolutely majority

The CSU saw big gains from its 43 percent score at the last election in 2008, when it lost its absolute majority.

About 9.5 million were eligible to vote in the wealthy, predominantly Catholic southern region that is home to industrial giants such as BMW, Audi and Siemens.

Pollsters said the poor showing in Bavaria by the FDP could in fact give them a boost in the September 22 general election.

Voters who would like to see the Merkel alliance continue and who are concerned about the FDP's poor showing in Bavaria might now want to give votes to the party, dragging on the conservatives' own score.

That prospect led many in the CDU to warn against any "pity" campaign for the FDP.

Merkel led a left-right grand coalition during her first four-year term.

At the last election in 2009, a resounding 14.6-percent result for the Free Democrats allowed Merkel to form a government with the conservatives' traditional allies.