By Michelle Martin

BERLIN (Reuters) - Half of Germans are concerned the surging number of asylum seekers in the country is overwhelming them and authorities, a survey showed on Thursday, underlining widespread unease about the country's ability to cope with an unprecedented influx.

Germany is the European Union's biggest recipient of asylum seekers, with the number expected to quadruple to 800,000 this year. Interior Minister Thomas de Maiziere has said Germany can cope with such a surge this year but not in the longer term.

The poll on the "Fears of the Germans" for R+V insurance firm was conducted before that drastically revised forecast became public so the number of Germans harboring concerns about the refugee crisis would probably have been far higher had it been conducted later, political scientist Manfred Schmidt said.

Germans in the former Communist east, where unemployment is generally higher than in the west and the far-right has a stronger grip, are more worried that Germany will be overburdened than their western counterparts, the poll showed.

Heidelberg University professor Schmidt said easterners generally had little experience of immigration and were less tolerant of foreign cultures than westerners. Some see themselves as "the losers of reunification" without a fair share of Germany's wealth, he said.

He said while Germany was used to immigration, in the past migrants had tended to come from former German territories, the former Communist East, the Soviet Union or other countries in the former eastern bloc. Now many are coming from the Middle East or southeastern Europe.

Almost one in two Germans thought relations with foreigners living here could deteriorate if more migrants arrive and the same number feared political extremism would rise. In recent weeks there have been almost daily attacks on shelters, with many suspected to have been carried out by the far-right.

Nonetheless, the Germans' top concern is the euro zone debt crisis, with two-thirds worried that they will have to cough up for a disproportionate share of the costs.

The annual "angst" poll of 2,373 people was conducted between June 5 and July 17.

(Reporting by Michelle Martin; Editing by Toby Chopra)