Glamour girl Stephanie Rice has come from the clouds to obliterate the world record in the 400m individual medley at the Olympic swimming trials.

The 19-year-old joined her boyfriend Eamon Sullivan as a record breaker by setting the mark of 4 minutes 31.46 seconds - some 1.43s below the time of American star Katie Hoff.

The Queenslander chopped almost six seconds off her best time to become the new favourite for the event at this year's Beijing Olympics.

The outgoing Rice couldn't contained herself after seeing the time.

"I think I swore and I thought oh I should not have said that, but I was so in shock," she said.

"I saw my time and I saw 3:31 because 3:37 was my best time but I did not think I would go that fast."

Rice, a bronze medallist at last year's world championships in the event, welcomed the pressure that would come her way as she produced the seventh world record this year - all have come in the new Speedo LZR Racer.

"(Coach Michael) Bohl said we don't want to be breaking world records here and I have done exactly the same thing as Eamon," she said.

"I have stirred it up and the pressure is on us now but I can take that, a world record has been my dream and I so glad that I got it."

Brisbane schoolgirl Emily Seebohm continued the assault on the history books by claiming the world record in the non-Olympic 50m backstroke.

The 15-year-old came within 0.01 of a second of the mark earlier this month before American Hayley McGregory seized the record a fortnight ago.

But Seebohm (27.95 seconds) showed she is on fire before the 100m by clipping 0.05 of a second off the mark and being the first under 28 seconds in the process.

The lanky swimmer was thanking everybody following the race.

"The goal was pretty much all this season to get that world record and being 0.01 off it last time I just had to go under 28 this time," she said.

And she was ready to pump up her state after being inspired by Stephanie Rice's world record in the 400m individual medley just minutes before hand.

"Aren't the Queenslanders just like the best," she said.

"I am going to be in the Guinness Book of world records."

It was the eighth world record of the year and all have been set in Speedo suits.

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