BERLIN, Oct 3 (Reuters) - Germany's liberal Free Democratic Party (FDP) pressed Chancellor Angela Merkel's conservatives to say whether they really want to lead a new coalition government, ramping up pressure on its would-be ruling partners ahead of exploratory talks on Sunday.
The conservatives' chancellor candidate, Armin Laschet, has said he wants to form a government, even after his bloc of Merkel's Christian Democrats (CDU) and Christian Social Union (CSU) slumped to a record low result in last Sunday's vote.
But Laschet was undermined last week when the leader of the Bavarian CSU, Markus Soeder, said the centre-left Social Democrats (SPD) - which narrowly secured the most votes - would most likely form a government.
The close election result, with no party getting an overall majority, has kicked off a period of complex negotiations that could last weeks or months, with the FDP and the Greens as possible kingmakers.
"The CDU and CSU must clarify whether they really want to lead a government," FDP leader Christian Lindner told the Bild am Sonntag newspaper.
"Some of the CDU's words speculate that negotiations with the SPD should fail first before the Union comes back into play," he said, referring to the CDU/CSU alliance known as "the Union". "That cannot be put upon our country."
The business-friendly FDP and the ecologist Greens, from opposite ends of the political spectrum and at odds on a range of issues, have moved centre stage after the SPD's narrow election victory - its first since 2012.
Both the SPD and CDU/CSU conservative bloc are courting the two smaller parties to get a parliamentary majority for a ruling coalition. Polls show voters would prefer the SPD to lead it.
The Greens would prefer the two smaller "kingmakers" to team up with the SPD, but the FDP is closer to the conservatives.
The conservatives and the FDP are due to hold exploratory talks later on Sunday. The SPD is also due to meet the FDP, as well as the Greens on Sunday.
Merkel, in power since 2005, plans to step down once a new government is formed and will stay on until that point.
