The European Central Bank can buy euro zone government debt on the secondary market but the scale and duration of the purchases must be limited, new German ECB Executive Board member Joerg Asmussen said on Friday, taking a cautious line on the divisive measure.

The ECB's bond purchases allowed disruptions to the central bank's monetary policy transmission mechanism to be remedied, Asmussen told German radio station SWR.

But they are limited in timeframe and volume. One has to say that very clearly, too, he added.

Asmussen has previously described himself as a pragmatist, but his comments suggest he does not favour boosting the bond buys to ease borrowing costs for crisis-hit euro zone states - a ploy politicians in France and beyond the bloc have pressed for.

Asmussen, previously Germany's deputy finance minister, joined the ECB at the start of the year, replacing former arch-hawk Juergen Stark who quit the bank over his opposition to the bank's controversial bond purchases.

The bond-purchase programme also led to the resignation last year of Bundesbank chief Axel Weber. His successor, Jens Weidmann, also opposes the plan - a measure that has created the deepest internal divisions at the ECB in its 13-year history.

Asked what could have been done differently after the fall of the U.S. investment bank Lehman Brothers, Asmussen said that the jury was still out on whether forcing banks to recapitalise or having them doing it voluntarily was the best way.

Turning to budget woes in euro zone countries, Asmussen said that budget consolidation is a must, but that it has to be accompanied by both growth strategies and improved cooperation on fiscal policy between countries sharing the euro currency.

(Reporting by Marc Jones and Paul Carrel; Editing by Hugh Lawson)