Seehofer was speaking Saturday to a party congress in Munich of the Bavaria-only CSU, which elected him party leader. He was the sole candidate. Of the 939 delegates, 786 voted in his favour and 84 against, with the rest not voting or spoiling their ballots.

The CSU was replacing its leadership after a state election debacle last month in which the CSU lost its absolute majority and must enter a coalition.

Delegates blamed the poll loss on Merkel, who leads the CSU's "sister party," the Christian Democratic Union. Though both parties are broadly conservative, the CDU has rejected a CSU plan to offer a larger tax rebate to commuters, bigger exemptions for heirs from inheritance tax and other tax cuts.

"We, the CSU, are a bundle of muscle," Seehofer, 59, told delegates at the congress, which approved with a huge majority his agreement with the smaller Free Democrat Party (FDP) to rule Bavaria jointly.

"My desk is possibly going to be Munich. But my fighting skills will also extend to Berlin," he said in reference to complaints that the CSU had too little influence within Merkel's three-party coalition.

The other federal coalition partner is the Social Democratic Party (SPD). Seehofer is to give up his post as federal minister of agriculture and consumer affairs.

For the first time in 46 years, the CSU is unable to rule the largely Catholic state of Bavaria without a coalition partner.

Seehofer said his objective as premier replacing Guenther Beckstein would be to restore the CSU's old strength, with 50 to 60 per cent of the popular vote. Four weeks ago the party won just 43 per cent of the votes in Bavaria.

The Bavarian legislature is to meet Monday to elect a new state premier and state government.

Broken promises?

Another western German state, Hesse was also poised to get a new government. After months of political manoeuvring, a Social Democratic (SPD) leader, Andrea Ypsilanti, 51, unveiled details of her bid to topple a conservative incumbent, Roland Koch, and seize the premiership of Hesse.

She said she would invite legislators to elect her as premier on Nov. 4, leading a minority coalition government with the Greens and counting on the votes of the Left party.

Merkel's Christian Democratic Union (CDU) immediately accused Ypsilanti of breaking a pre-election promise not to ally with the Left, which embraces former East German communists and western leftists.

In the state capital of Wiesbaden, Ypsilanti unveiled details of a coalition agreement with leaders of the environmentalist Greens party. They would promote investment in renewable energy and delay the expansion of Frankfurt's airport.

Koch narrowly lost a state legislative election nine months ago. As caretaker premier since, he has sought to weaken the three competing parties which oppose him and has criticized their plans for a loose alliance to vote him out of office. Just two legislators breaking ranks could thwart Ypsilanti's ambitions.

Second female premier

She would not be Germany's first woman state premier, but follows in the Social Democratic footsteps of Heide Simonis, who ran the state of Schleswig-Holstein from 1993 till 2005.

Ypsilanti said her government would comprise 10 Social Democrat ministers and two Greens, including the Greens leader Tarek Al-Wazir as environment minister. The environmentalists oppose expansion of the airport, which they say already causes too much noise and spoils the landscape. The coalition is to seek a ban on night landings.

In Berlin, CDU general secretary Ronald Pofalla called the new Hesse alliance a "reckless political experiment" based on the SPD "breaking a promise" not to link up with the Left in the west. The CDU has suggested that the SPD may ultimately seek a federal alliance with the Left, which is anathema to many voters in western Germany. Ypsilanti has also faced opposition to the alliance in her own SPD ranks.