Earlier this year, the European Central Bank was memorably described by a US economist, Carl Weinberg, as "an untested kitten in the jungle of central banking".

To the contrary, some would argue that under the stewardship of Wim Duisenberg, the ECB president, the ECB has proved to be a kitten that is not afraid to show its claws.

Since the ECB took control of monetary policy in the euro-zone in January 1999, the burly, plain-spoken but often humorous Mr Duisenberg has firmly defended the young central bank's independence from political pressure.

In the first three months of 1999, he saw off an attempt by Oskar Lafontaine, the leftist former German finance minister, to force interest rate cuts and create a system of managed international exchange rates.

With some success, Mr Duisenberg has also insisted that the euro-zone's 11 national governments must grasp the nettle of structural economic reform by reforming tax systems and labour markets.

At the same time, conscious that its primary task is to contain inflation, the ECB has raised interest rates six times since last November. The full effect of these rate increases has yet to come through, but the ECB's careful approach to monetary policy has helped guide the euro-zone economy into its strongest phase of growth for a decade.

For several reasons, the past 20 months have been a difficult balancing act for the 65-year-old, Dutch-born Mr Duisenberg. His period in office has been complicated by the fact that inflationary pressures have grown stronger at exactly the same time as the euro's value has fallen sharply on foreign exchange markets.

Aware that he is in many ways "Mr Euro", the public face of European monetary union, Mr Duisenberg has sought to reassure the euro-zone's almost 300m citizens that their income and savings are secure, whatever may happen to the euro-dollar exchange rate.

This has required him to avoid making an explicit link between monetary policy and the euro's external exchange rate, while nevertheless raising interest rates sufficiently to keep inflation at bay.

A stronger dose of monetary policy medicine might have satisfied those who want the ECB to be as ruthless as the Bundesbank of old in stamping out inflation. But it would have handed extra ammunition to critics who already accuse the ECB of failing to give a sufficient boost to economic growth in the euro-zone.

On the ECB's 17-strong policy-making Governing Council, Mr Duisenberg has been required to forge a consensus between those members pushing for faster or larger rate rises and others content with a milder tightening cycle.

With council members and officials from various national central banks making frequent public statements in the form of formal speeches, interviews and other remarks, financial market participants have often criticised the ECB for failing to deliver a clear, coherent message.

Foreign exchange dealers who watch Mr Duisenberg's monthly press conferences, usually held in Frankfurt immediately after an ECB council meeting, complain that he sometimes appears to contradict himself.

Ironically, these appearances in front of the media are intended as a serious effort to show that, far from being secretive and unaccountable, the ECB wants to communicate quickly and effectively with financial markets and the general public.

"As far as I am aware, no other central bank regularly communicates in such a prompt and open manner with the public immediately after its monetary policy meetings," says Mr Duisenberg.

"Some criticise our strategy for not being sufficiently simple, arguing that we should focus only on one indicator, be it money or an inflation forecast," he adds. "To these critics, I can say that our strategy is honest. It reflects the complex environment we are living in - an environment in which policy decisions cannot be simply related to one information variable."

Under Mr Duisenberg's leadership, the ECB has become more willing to sketch out its forecasts for inflation and growth in the euro-zone, without tying itself down to specific predictions.

Some of Mr Duisenberg's difficulties may be traced to the process by which he was selected as the ECB's first president. In the view of critics such as Valery Giscard d'Estaing, the former French president, it was a choice that damaged the ECB from the start.

"I have always thought that the central bank's first president should be a man whose international authority would be immediately recognised," Mr Giscard d'Estaing said recently.

"In fact, contrary to the spirit of the [European Union's Maastricht] treaty, the club of member-state governors named one of their own from a medium-sized country, the Netherlands, to head the ECB. Whatever the personal merits of Mr Duisenberg, it was a casting mistake."

Mr Giscard d'Estaing will get his way if, as expected, Jean-Claude Trichet, the Bank of France governor, succeeds Mr Duisenberg as ECB president in the second half of 2002.

By that time, Mr Duisenberg says he will be happy to bow out, once the ECB has overseen the introduction of euro banknotes and coins in the euro-zone.