Canada's Penny Oleksiak has withdrawn from the upcoming world aquatics championships due to a whereabouts issue under anti-doping rules, she announced on social media Friday.

The 25-year-old Toronto native, Canada's most decorated female Olympian, said the matter "does not involve any banned substance" and added, "I am and always have been a clean athlete and will be making no further comment at this time."

Swimming Canada said Oleksiak was not sanctioned, but withdrew voluntarily.

Swimming Canada CEO Suzanne Paulins said Oleksiak failed to keep her whereabouts information fully up to date with World Aquatics but described it as "an administrative mistake."

"We support her decision and believe she is a clean athlete who made an administrative mistake," Paulins said in a statement. "This is a team-first decision, as while she has not been sanctioned at this time, participating at world championships could potentially affect team results if an anti-doping rule violation is determined."

Paulins added that athletes are responsible for submitting whereabouts filings on time to comply with anti-doping rules and avoid sanctions.

"Anti-doping regulations are in place to ensure a level playing field for all athletes, and we are committed to the enforcement and support of all anti-doping rules as outlined in the Canadian Anti-Doping Program and through World Aquatics and the World Anti-Doping Agency," she said.

The world championships run from July 11 to Aug. 3 in Singapore.

Oleksiak is a seven-time Olympic medallist and nine-time world championship medallist.