BRISBANE -- Australia's Olympic 400 meters gold medalist Cathy Freeman won her sixth national title on Friday but said afterward she would struggle to be in top form for this year's world championships.

Freeman won the final in 51.66 seconds which was her fastest time in the event since the Sydney Games, Reuters reported.

"The way I'm going it's easy to think I'm not going to be in peak condition come (the world championships in Paris in) August," Freeman told reporters.

"The more I race, especially after Sydney (when she was thrashed last month by Australia's 400 meters hurdles Commonwealth Games champion Jana Pittman) the more I want it -- there's no denying that.

"I'm nowhere near hitting the mark where it all falls into place," added the two-times former 400 meters world champion.