VIENNA (Reuters) - Austria’s Chancellor Christian Kern said the Freedom Party (FPO) must leave the far-right faction in the European Parliament if it wants to enter a coalition government with his center-left party.

FILE PHOTO: Austrian Chancellor Christian Kern attends a session of the St. Petersburg International Economic Forum (SPIEF), Russia, June 2, 2017. REUTERS/Mikhail Metzel/TASS/Host Photo Agency/Pool

Kern’s Social Democratic Party (SPO) last week dropped a 30-year ban on allying with the anti-immigration FPO, but set broad conditions for any potential coalition partner to fulfill.

Adding a new condition, Kern told Wednesday’s edition of newspaper Oberoesterreichische Nachrichten: “As long as ... the FPO shares a faction with (French far-right leader) Marine Le Pen... the preconditions for deeper cooperation have not been met.”

For most center-left parties in Europe, a coalition government with the far right would be unthinkable.

But polls suggest the FPO might well become kingmaker after a snap parliamentary election set for October following frequent spats within the current coalition between the SPO and the center-right OVP.

The FPO joined forces in the European Parliament in 2015 with Le Pen’s National Front, the Netherlands’ Geert Wilders and far-right leaders from Italy and Belgium to form the Europe of Nations and Freedom bloc.

Le Pen campaigned on a staunchly anti-EU platform in France’s presidential election this spring but was well beaten in last month’s run-off, prompting the FPO to tone down its euroscepticism.

The FPO has said it has no preference between allying with the SPO and the center-right OVP, but party secretary general Herbert Kickl said on Wednesday an alliance with the Social Democrats was not currently on its agenda.

“As things stand at present we are not available for coalition talks with the SPO,” he told newspaper Der Standard.

Kickl said he wanted the SPO’s party base to vote on the possibility of an alliance with the FPO before the Oct. 15 election. Kern wants such a vote to take place only after any coalition talks have been completed.

Last week’s decision to replace the SPO’s ban with a “values compass” and flexible criteria for any potential partner was taken by the party’s 70-person steering committee.