By Paul Carrel
BERLIN (Reuters) - Germany's liberal Free Democratic Party (FDP) hopes to reclaim its traditional role as kingmaker after September's national election, but its leader proved coy on Tuesday over which of the two main parties it might join in coalition.
The business-friendly FDP was the junior partner in Chancellor Angela Merkel's 2009-13 conservative-led coalition but failed to clear the 5 percent threshold to win seats in the current lower house Bundestag. Media reports suggest it is now being courted by the centre-left Social Democrats (SPD) as a possible alternative partner to the far-left Linke.
Opinion polls suggest six party groups, including the FDP, will enter parliament after the Sept. 24 election, up from four now. Neither Merkel's conservatives nor the SPD would be able to govern alone, opening the way for talks with smaller parties in their efforts to forge a stable coalition government.
FDP leader Christian Lindner appeared to play down the possibility of a tie-up with Martin Schulz's SPD, which he accused of wanting to strangle German business with red tape, but he also ruled nothing out.
"Schulz wants redistribution (of incomes), for the state to command the economy, more bureaucracy," Lindner told broadcaster n-tv. "Merkel basically wants to change nothing in Germany ... At least she doesn't want to go backwards."
Pressed on which party would be his preferred coalition partner, Lindner said: "That depends on the (policy) content. If it is not possible to implement (our policy) content in a government, then we will go into opposition."
An Emnid poll on Saturday showed Merkel's conservative bloc winning 35 percent, the SPD 31 percent, the Linke and the anti-immigration Alternative for Germany (AfD) both on 9 percent, the Greens on 7 percent and the FDP on 6 percent.
Merkel's conservatives now rule in a 'grand coalition' with the SPD, though neither is keen to repeat the right-left partnership. A re-run would be "not ideal", senior conservative Jens Spahn told the daily Frankfurter Allgemeine Zeitung.
Underlining the FDP's credentials as a potential ally, Spahn said the liberals were closest on policy to the conservatives.
"That would be a good constellation with regard to economic developments as well," he said in pre-released comments to run in the paper's Wednesday edition, adding: "We could finally lower taxes together."
The FDP wants to cut taxes while also increasing investment in education and digital infrastructure by privatising state assets.
The FDP has more often joined conservative-led federal governments in the past, though it served in SPD-led coalitions from 1969 to 1982 and more recently has governed with the Social Democrats at the regional level.
Schulz has led a revival in the SPD's poll ratings since being nominated in January to challenge Merkel in her bid for a fourth term as chancellor.
But his party stumbled in a regional election in the western state of Saarland late last month, with voters flocking to Merkel's conservatives for fear of the SPD joining forces with the Linke to form a left-wing alliance.
The prospect of a coalition with the FDP might prove more popular with centrist-minded voters, but Lindner described reports of the SPD scoping out such a tie-up as "tactical, a diversion from the Linke party option".
Lawmakers in Merkel's conservative bloc say privately they believe the FDP is hungry for power after four years in the political wilderness and believe the party could join a left-leaning coalition to get back into government.
(Writing by Paul Carrel; Editing by Gareth Jones)