Afghan President Hamid Karzai is "corrupt" but NATO has to accept that "he is our guy" in the country, French Foreign Minister Bernard Kouchner said, according to the New York Times on Thursday.

Kouchner also complained that President Barack Obama's US administration was drawing up a new strategy for the war in Afghanistan without consulting its European allies within NATO, leaving them in the dark.

"What is the goal? What is the road? And in the name of what?" Kouchner asked, according to the New York Times report.

"Where are the Americans? It begins to be a problem ... We need to talk to each other as allies."

Karzai was named president for his second term on Monday after a chaotic election in which the first round results were marred by massive fraud and the second round abandoned after his main opponent dropped out in disgust.

Nevertheless, Kouchner said the allies had no choice but to work with him in order to get the mission in Afghanistan back on track and start building a state capable of protecting its people and holding of the Taliban.

"Karzai is corrupt, OK," he said, according to the Times. "We have to legitimise him."

France has given Karzai a nine-point plan it feels will help him reform his government and has urged him to find a way to work with his bitter defeated election rival, former foreign minister Abdullah Abdullah.