The appointment of Janet Yellen as the next US Treasury Secretary is good news for the global economy as the former Federal Reserve chair is aware of the global ramifications of her country's policy, the vice president of the European Central Bank said. 

"Janet Yellen knows perfectly what the US economy needs and she is perfectly aware of the implications that the economic policy of the US is going to have on the world economy," Luis de Guindos said at a news conference. 

"The appointment of Janet Yellen is good news for the US economy and the global economy," he added. 

The ECB has criticised Donald Trump's outgoing administration for its protectionist stance and was attacked by the US president over the euro-dollar exchange rate. 

Yellen, 74, brings decades of economic policy experience and is respected by Congress, international finance officials, progressives and business interests alike. 

She has called for opening fiscal spending taps to revive an economy wracked by the coronavirus pandemic and would be the first person to head the Treasury, the Fed and the White House Council of Economic Advisers. 

The post will present a host of new challenges for Yellen, whose policymaking experience in the past 20 years has largely centered on monetary - rather than fiscal - policy.

It means a far more political role than that she played in her long career at the Fed, an institution that goes to great lengths to distance itself from partisan politics.

Janet Yellen made history in 2014 when she became the first woman to chair the Federal Reserve after serving for a decade as San Francisco Fed president and a Fed governor. 

Republican President Donald Trump declined to renew her term and replaced her with current Fed Chair Jerome Powell in 2018.