Dr Angela Merkel is under fire as never before in the past two years, her popularity wilting among both ordinary Germans and political allies for her accommodating refugee policy.

Three weekend surveys showed the German Chancellor's popularity has dipped significantly for the first time in the current 2013 to 2017 legislative period.

Rumblings about her ability to lead the conservatives at the next general election have also surfaced.

Germany's generous social welfare has attracted the biggest number of people fleeing conflict in places such as the Middle East and Africa. It expects at least 800,000 asylum seekers this year, four times last year's level.

The decision by Dr Merkel to let in Syrian refugees stuck in pitiful conditions in Hungary was a humanitarian gesture. But it sparked a mad rush by refugees to get to Germany last month, leaving officials scrambling to house them in sports stadiums, school gyms, trade fair grounds, army barracks, abandoned buildings and containers.

The onset of cold autumn weather in Europe will likely worsen the refugee housing problem - and the public mood. More and more Germans are wondering how they can be integrated.

German President Joachim Gauck said on Sunday Dr Merkel's decision has been met by "enthusiastic approval" among Germans, but has also had reactions of "clear reserve, yes, even rejection".

He added that many are worried and asking "will the influx overburden us eventually".

Dr Gauck said the government will have to "promote the construction of apartments and build schools, hire teachers and kindergarten staff, adjust the labour market and vocational training, teach the German language and law - and do all of that at the same time".

Professor Gero Neugebauer, a political scientist at Free University of Berlin, said Dr Merkel has coped well in the euro zone crisis, the Russia/Ukraine conflict and Greece debts because the other players were non-Germans.

"But now, there are many other domestic parties weighing in, such as leaders of municipalities, towns and cities," he said. "And, up to now, Merkel is unable to say what's the cost of all of these, which is a concern for the Germans."

He said that while Dr Merkel has no strong conservative rival, a very small minority in the party's grassroots has started to ask whether she can remain popular enough to win votes again in 2017, when she is expected to seek a fourth term.

Weekly newspaper Die Zeit said Dr Merkel's decision to open Germany to the refugees may have been the "most spectacular and most far-reaching" of her chancellorship.

It added: "It could also be the decision with which the party chief has alienated her CDU (Christian Democratic Union) like never before. Has Merkel, at the apex of her power, engineered her own demise and even her fall from power?"

A ZDF television survey said a majority of Germans still believed Germany is able to handle the huge number of asylum seekers in the country, but the figure is now 57 per cent, compared with 62 per cent two weeks earlier.

Mr Horst Seehofer, the head of the Christian Social Union (CSU), the CDU's Bavarian sister party, has led the conservative front's charge against Dr Merkel. He called her decision a "mistake" from the start as refugees arriving in Munich's central train station overwhelmed social workers and volunteers in Bavaria's capital.

Mr Seehofer is also Bavaria's Premier, whose followers gave Dr Merkel's CDU victory in the state. Mr Seehofer's raw tone, as significant as it is unusual for its very public bluntness, followed through with a provocative gesture - inviting Hungarian Prime Minister Viktor Orban to join the CSU party's meeting last week. Mr Orban is now the EU bogeyman for his border barbed wires, tear gas and water cannon trained on refugees.

On Sept 22, at a closed-door CDU/CSU Parliamentary Group meeting, Dr Merkel was criticised for three hours, media reports said. Former interior minister Hans-Peter Friedrich demanded an upper limit for refugee acceptances.

Two days later, Interior Minister Thomas de Maiziere blamed Dr Merkel indirectly for the refuge influx. He told a TV talk show: "It has gotten out of control with the decision to draw out the people from Hungary to Germany."

The government's re-imposition of border controls returned some semblance of order and its recent deal for the federal government to raise financial assistance to 16 federal states from €2 billion (S$3.2 billion) this year to about €4 billion next year calmed the frayed nerves of local officials. They also agreed on speedy deportation of those whose application for refugee status is rejected and the replacement of "pocket money" given to asylum seekers with "benefits in kind".

Some critics said the deal meant a reversal of Dr Merkel's position.

"This is a complete about-face. It is actually a tightening of Germany's asylum laws," said spokesman Max Pichl of refugee rights group Pro Asyl.