Nissan Motor Co <7201.T> may have to delay U.S. production of its Leaf electric car as a result of the March 11 earthquake that rocked northern Japan, an executive said on Monday.

After the earthquake, every operation stopped, said Hideaki Watanabe, Nissan vice president for zero-emission vehicles. All the resources were put in place to restore Japan.

As a result, the Japanese automaker halted its efforts to plan for the U.S. production of the Leaf, he said. He declined to say how long the delay could last.

Nissan is currently planning to start making the Leaf at its plant in Smyrna, Tennessee by late next year. Battery production is slated to begin in September 2012.

We're really trying to push to minimize the lead time, Watanabe told reporters. I would admit there is a risk, but it would be too early to say how much.

The zero-emission Leaf represents Nissan's bid under Chief Executive Carlos Ghosn to take the lead in the emerging market for electric vehicles along with its French partner Renault SA .

The automaker launched the five-seater Leaf in Japan and the United States in December.

Even before the earthquake, the rollout of the Leaf was rocky. In April, restart problems were reported in some electric Leaf cars and some customers have complained of slow deliveries.

Watanabe said communication with customers has not been as good as Nissan expected, adding that Nissan would improve.

The company expects that more than 80 percent of the parts used to make the Leaf at the U.S. plant will come from local suppliers, Watanabe said.

The Leaf is currently sold in California, Washington, Oregon, Arizona, Tennessee, Hawaii and Texas. This summer, dealers in Maryland, Virginia, North Carolina, South Carolina, Georgia, Florida and Alabama will also begin selling the car.

(Reporting by Deepa Seetharaman; Editing by Tim Dobbyn)