Germany has criticized a call for the eurozone to boost its financial firewall to €1 trillion ($1.3 trillion), arguing that demanding ever-higher sums only unsettles markets.

The Organization for Economic Cooperation and Development made its call on Tuesday.

It came after Germany signaled it will support a temporary increase of the lending capacity of the eurozone's two bailout funds to around €700 billion.

Chancellor Angela Merkel's spokesman, Steffen Seibert, said Wednesday: "It is regrettable that apparently no figure is ever high enough in this discussion."

Germany has Europe's biggest economy and has made the largest contribution among eurozone countries to rescue efforts for the 17-nation currency bloc, although it sometimes has been a reluctant financier.

Seibert argued that advocates of a much-increased firewall overlook questions over whether countries could credibly finance it. He added: "the result of such proposals ... is unfortunately that markets are unsettled again and again."

He added that there has been a period of quiet lately and a meeting later this week of Europe finance ministers — which is to discuss the funds' lending capacity — was meant to help calm them.

"We shouldn't endanger that," he said.

The criticism comes on the same day that Italian Prime Minister Mario Monti blamed Germany for its role in the European debt crisis.

Monti said that because Germany and France both ignored maximum deficit targets, it set a bad example for smaller nations and contributed to the present debt situation.