Australia's Anna Meares claimed her fourth title in the women's 500 metre time trial in a world record time at the track cycling world championships Sunday.

Eight years after claiming her maiden gold in the two-lap race against the clock, also in Melbourne, Meares continued to show she will be a strong medal contender at the London Olympics where she will aim for triple gold.

Meares' time of 33.010sec in the 500m -- a non-Olympic event -- beat the previous best time of 33.296sec set by Simona Krupeckaite of Lithuania at the 2009 world championships in Pruszkow, Poland.

It is Meares' second world record of the championships. The 28-year-old Queenslander also beat Krupeckaite's world mark of 10.793, set in 2010, for the 200-metre flying start in 10.782.

Meares goes home with four medals -- two gold, a silver and a bronze -- from the championships, the last big hit-out for the track superpowers before the London Games this summer.

She claimed a silver with partner Kaarle McCulloch Wednesday in the women's two-lap team sprint, won by Germany's Miriam Welte and Kristina Vogel in a world record time.

Having missed out on the sprint gold on Friday when she finished third behind six-time world champion Victoria Pendleton of Britain, Meares bounced back in style 24 hours later to dominate the women's keirin.

Meares also won the 500m title in 2007 and 2010.

In London she will compete in the sprint, team sprint and keirin.