The Free Democratic Party's national executive board decided at its meeting Monday in Berlin to postpone a final decision about the party's prospective new leader by one day.

But speculation is rife that Health Minister Philipp Rösler, who also heads the FDP in the state of Lower Saxony, might become the new head of the junior partners in Chancellor Angela Merkel's coalition government. As Rösler is already a member of Merkel's cabinet, the 38-year-old politician might well succeed Westerwelle as deputy chancellor as well.

FDP deputy party leader Christian Lindner, 32, is also in the running.

Any leadership candidate nominated by the board must be officially voted into office by FDP members at their party conference in May in the eastern city of Rostock.

Untenable position

"We must correct mistakes made in the past and set new priorities," Daniel Bahr, FDP regional party leader in the state of North Rhine-Westphalia, told German public radio on Monday.

"A change in personnel is not enough," he added. "We have to discuss the entire team line-up."

Westerwelle, who led the FDP to its best-ever national election result of just under 15 percent in 2009, has been blamed for plummeting popularity ratings since the party became the junior coalition partner in Berlin, culminating in embarrassing losses in three state elections last month.

The pro-business party has been beset by infighting over health care, energy policy and taxes - one of the FDP's key issues.

"The FDP has suffered an unparalleled loss of credibility since they re-entered the government in 2009, and their misery is due to one person: Westerwelle," said Manfred Güllner, head of the Forsa polling institute.

Most unpopular politician

On Sunday, Westerwelle gave in to relentless pressure to resign leadership of the party after 10 years at the helm. He announced he would relinquish his post as vice chancellor as well, and said he intended to focus on his job as foreign minister.

But it is unclear how long Westerwelle will be able to hold on to that post, as his standing has suffered not only with his party but also among the wider electorate.

The three opposition parties, the Social Democrats, the Greens and the Left, have called for Westerwelle to resign the Foreign Ministry.

"He can't stay on in the one post and not the other. This is a matter of German standing in the world," said Renate Künast and Jürgen Trittin, the Greens' parliamentary co-leaders.

Author: Dagmar Breitenbach (Reuters, dpa, AFP, AP)
Editor: Nicole Goebel