Olympic and world shot put champion Valerie Adams has applauded athletics' world governing body for trying to make the sport as free of drugs as possible.
The International Association of Athletics Federations has retested of a selection of samples from the 2005 world championships had found doping by six athletes.
They include Adams' great Belarusian rival Nazdeya Ostapchuk, who won the event in Helsinki, while the Aucklander finished third.
Adams, who is competing in the Sydney Track Classic on Saturday night, was unavailable for comment but issued a brief statement.
"It is fantastic that the IAAF are working hard to uncover drug cheats and are focused on maintaining the integrity of the sport," she said.
"I find it very motivating that the world governing body is committed to making the sport of athletics as clean as possible."
Adams has won the three world titles up for grabs since Helsinki.
She is also the two-time Olympic champion, her second gold coming from the London Games last year after the medal was stripped from Ostapchuk for testing positive.
IAAF deputy general secretary Nick Davies said the retesting of the 2005 samples was carried out to capitalise on the latest technology and equipment.
"We have an eight-year statute of limitations on anti-doping, so seven years past the event is really when you want to test, using the most up-to-date equipment," he told BBC Sport.
"The message we're trying to give out is: 'Don't even think about it, because even six or seven years down the road, something you think you got away with you won't.'"
The five other athletes found out by the retesting were three other Belarusians in shot putter Andrei Mikhnevich, and hammer throwers Ivan Tsikhan and Vadim Devyatovskiy; and two Russians in long jumper Tatyana Kotova and hammer thrower Olga Kuzenkova.
The IAAF has initiated disciplinary procedures, which are ongoing.
The Sun newspaper reported that Ostapchuk, suspended for a year after the London Olympics, now faces a lifetime ban.