NATO chief Jens Stoltenberg urged Germany on a visit to Berlin Wednesday to mirror its leadership role in Europe as the bloc's biggest economy in its defence spending.

Describing Germany as a "staunch and important" NATO ally, Stoltenberg stressed the need for members of the US-led alliance to bump up investment amid challenges such as the Islamic State jihadist group or the Ukraine crisis.

"Germany is providing leadership in so many areas in Europe, but we are also looking for German leadership when it comes to investing in defence," the alliance chief told a joint press conference with Chancellor Angela Merkel.

"We need to invest in our defence to be able to protect all our allies and to maintain the security and stability of Europe," the former Norwegian premier, who took over the NATO helm in October, added.

At a NATO summit in September in Wales dominated by the fallout from the Ukraine crisis, the 28 alliance leaders committed to increase defence spending to two percent of annual economic output within 10 years.

Meanwhile Stoltenberg welcomed German involvement in Afghanistan and developing a high-speed NATO reaction force.

Germany's Die Welt daily, which published an interview with Stoltenberg Tuesday, said that Berlin's defence expenditure was under the NATO target, at 1.3 percent of gross domestic product.

The NATO chief, in the interview, welcomed a nominal increase in German spending for 2015 but underscored that the US government had recently made one billion dollars available for safeguarding Europe.

Germany has faced criticism in the past over its perceived reluctance in foreign and security matters, and long faced calls for it to pull its weight in NATO and elsewhere on a par with its economic might.

Several political leaders last year called for Germany to take more responsibility in international crises.

But the country faced embarrassing hiccups in sending German arms to Peshmerga Kurdish fighters battling IS -- a watershed decision for Berlin -- and revelations about wider deficiencies in defence hardware.