Sweden kicked off its six-month European Union presidency Wednesday amid fears the bloc's unresolved institutional woes may overshadow its priorities of tackling climate change and the economic crisis.

"Now is not the time to look inwards and look at institutional questions," Swedish Prime Minister Fredrik Reinfeldt told reporters at a press conference in Stockholm.

"Now is the time to show leadership," in particular ahead of a global summit on reducing greenhouse gases in December in Copenhagen, and for that "we need clarity," he said.

That clarity is clearly lacking in European institutions.

The most urgent problem facing Sweden's presidency is that it risks finding itself with a lame duck president of the European Commission.

European leaders in mid-June gave Jose Manuel Barroso their lukewarm support for his re-election for a second five-year term, and the European parliament, which must also vote on the matter, has indicated it could postpone its decision until the autumn.

That would prolong the uncertainty and could give Barroso's critics on the left, the Greens and even the liberals, time to come up with a rival candidate.

Aware of this risk, Barroso urged EU parliamentarians to find a rapid solution.

The European parliament is expected to announce on July 9 whether or not it will postpone its vote.

"We should have clarity as soon as possible ... I hope the decisions will be taken in a way that will reinforce and not weaken the European institutions," Barroso said.