FRANKFURT--Germany's central-bank chief Jens Weidmann criticized the European Central Bank's new measures to stimulate Europe's weak economy and boost inflation, according to a media report on Sunday.

In an interview with German weekly Der Spiegel, the Bundesbank president was particularly critical of the September announcement by the ECB to buy bundled bank loans known as asset-backed securities.

The ABS program, which is expected to kick off in October, forms part of ECB efforts to improve the supply of credit in the euro zone. In an ABS, banks bundle loans they have made to companies or households, which can then be sold to other investors.

"Depending on how the ABS-purchase program is designed, there is a danger that banks could be exempt from risks at the expense of taxpayers," Mr. Weidmann said. That is why it is essential, "[the central bank] accepts no significant risks of individual financial institutions or countries," he said.

Mr. Weidmann is an ECB Governing Council member.

If the ECB buys anything at all, Mr. Weidmann said, it should only buy low-risk securities. But it is "questionable" whether there are enough of these in circulation for the central bank to reach its purchase targets, he said.

In addition to the ABS program, the euro zone's central bank in September cut three main interest rates. ECB President Mario Draghi also suggested quantitative easing is still on the table. The measures are aimed at boosting inflation, which at an annual rate of 0.3% in August, is far below the ECB's target of a little below 2% over the medium term. The figure for August was revised upward to 0.4% but the annual rate of inflation in the euro zone still remained at the lowest level since Oct 2009.

Mr. Weidmann, who is known for his criticism of the ECB, said the package of measures represents a fundamental strategy and a drastic change for ECB monetary policy.

"Regardless of one's stance on the content of the measures, the majority of the ECB governing council has, through their decisions, signalized that monetary policy is ready to go very far and to enter new territory," he said.

But massive central-bank purchases of government bonds only address the symptoms of the economic crisis and don't heal the root causes, Mr. Weidmann said.

The ECB's balance sheet has been shrinking in recent years, but other major central banks such as the Federal Reserve and the Bank of Japan have been expanding theirs through large-scale purchases of public and private debt, a policy known as quantitative easing.

Analysts have said the ECB could follow suit if its new loan program fails to help stimulate demand for goods and services and thereby also fails to raise annual inflation.

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