LONDON (Reuters) - Ranomi Kromowidjojo of the Netherlands sent a warning to her rivals that she remains the woman to beat in the women's 100 meters freestyle at the London Olympics after posting the fastest qualifying time on Wednesday.

After conserving her energy in the morning heat, the flying Dutchwoman hit the accelerator in the evening's semi-finals, stopping the clock at 53.05 seconds, a new Olympic record.

"I am feeling quite good," she said. "There was not much movement in the pool.

"I got out of the pool quickly because I have to get ready for the next race."

Australia's Melanie Schlanger was second fastest, but still more than a third of a second behind Kromowidjojo, while American teenager Missy Franklin was third quickest.

Germany's defending Olympic champion Britta Steffen failed to make the eight-woman final after finishing 12th.

"I'm happy with the time. I did how I planned. I've improved through the heats." Steffen said.

"I'm sad that I didn't reach the final of course. I don't know why but I gave it 100 per cent."

(Reporting by Julian Linden; Editing by Greg Stutchbury)