ROME (Reuters) - Italy’s anti-establishment 5-Star Movement opened the door to coalition talks with the center-left Democratic Party (PD) on Tuesday, saying the only other way to end a political deadlock would be a return to the polls.

Italian politics have been in limbo since an inconclusive vote on March 4, which saw a center-right alliance led by the anti-immigrant League win the most seats and the 5-Star emerge as the biggest single party. The PD came a distant third.

No group or bloc came close to winning an outright majority, but mutual recriminations and deep-rooted rivalries have so far stymied all efforts at putting together a coalition in the euro zone’s third largest economy.

Statements on Tuesday by 5-Star leader Luigi Di Maio and the acting head of the PD, Maurizio Martina, offered a glimmer of hope that the stalemate could be broken, but misgivings in both groups might yet derail any joint initiative.

“I ask the PD to come to the table, not to sign a (government) contract immediately, but to see if there are the grounds for putting one together,” Di Maio told reporters.

He acknowledged that weeks of discussions with League chief Matteo Salvini had led nowhere, the talks floundering on 5-Star demands that the League abandon its electoral allies, including Forza Italia, led by former Prime Minister Silvio Berlusconi.

“Matteo Salvini and the League have opted for irrelevance,” Di Maio said following talks with the speaker of the lower house of parliament, who has been asked by the head of state to sound out the possibility of deal between 5-Star and PD.

Increasingly annoyed by the prolonged impasse, President Sergio Mattarella has given the lower house leader Roberto Fico until Thursday to report back with his findings.

REGIONAL VOTE

The PD has always insisted since suffering a heavy defeat last month that it would go into opposition. However, after meeting Fico, the party’s leadership said it would consider talks with Di Maio if he publicly backed away from the League.

Within two hours, Di Maio confirmed that he was ending contact with the League, earning a swift rebuke from Salvini.

“Flirting with ... the PD, just to gain power, seems highly disrespectful to Italians and his own voters,” said the League leader, who is campaigning before an election in the north eastern region of Friuli-Venezia-Giulia set for Sunday.

Political sources have told Reuters that serious government talks would start only once this regional vote was finished, meaning an eventual 5-Star-League alliance might still happen.

Opinion polls have consistently said that a coalition involving these two parties is the preferred option for most Italians and there would be considerable opposition within both PD and 5-Star ranks to any alliance between them.

After Martina announced he would be ready, in principle, to hold talks with 5-Star, a number of lawmakers close to the PD’s previous chief, former prime minister Matteo Renzi, sent messages on Twitter that read #senzadime (WithoutMe).

Di Maio also acknowledged there would be dissent within his own group and said any eventual government pact would be put to a vote to 5-Star members on their Internet platform.

If the PD initiative ultimately failed, he said his group would not back any mooted attempt to create a cross-party government of technocrats -- a mechanism used by previous presidents to overcome political crises.

“If this path (with the PD) were to fail... then in our opinion there should be another election,” he said.