SHANGHAI, Oct 4 (Reuters) - Formula One stewards summoned Lewis Hamilton on Thursday after complaints that the Formula One championship leader drove erratically behind the safety car in a wet Japanese Grand Prix last weekend.

"New evidence has emerged and the stewards are looking into it," said a spokesman for the International AutomobileFederation (FIA).

"We can't pre-empt the stewards' discussion, let alone the decision," he added when asked what sanction the McLaren driver might face.

A decision was expected at the Chinese Grand Prix on Friday after another meeting of the stewards.

Red Bull's Australian Mark Webber was shunted out of the race by Toro Rosso's German rookie Sebastian Vettel while in second place following Hamilton with the safety car deployed and both complained that his driving was a contributory factor.

Webber and Vettel, who was blamed for the accident and given a 10-place penalty on the grid for this weekend's race, collided at Fuji while in second and third places respectively.

Hamilton's win left the 22-year-old British rookie in a position to clinch the title in China. He leads double world
champion team mate Fernando Alonso by 12 points with two races remaining.

RUNNING WIDE

Toro Rosso is Red Bull's sister team and both drivers said on Thursday that Hamilton had contributed to the accident by running wide and slowing while the safety car continued on the normal line.

Webber told a news conference in Shanghai that he thought Hamilton did a terrible job driving behind the safety car.

"It definitely contributed to Sebastian hitting me up the back because he (Hamilton) wasn't doing what he was supposed to be doing," added Webber.

"He spoke in the drivers' meeting about how good a job he was going to do and he did the opposite. Still, we know for next time."

Under Formula One rules, stewards can review decisions if new evidence emerges.

The sporting regulations also say the race leader must keep a standard distance behind the safety car.

"When I was behind him it felt really inconsistent," said Honda's Jenson Button. "I don't know what he was doing really.

"He came through the last section and he kept slowing down," added Button, who had been fourth at Fuji during an earlier safety car period.

"He knew the safety car wasn't coming in and he kept hitting the brakes hard in the last sector so everyone would bunch up.

Then he'd shoot off and brake again," added the Briton.

"It was quite strange and it normally only happened in the last sector."

Vettel said Hamilton's movement had been so extreme that he thought the McLaren driver was retiring from the race.

"I was wondering what happened to him, I already thought he's retiring, there's no more power...by the time I looked back in front of me, I was already in Mark's rear."