Former two-time Olympic silver medalist canoeist Nathan Baggaley and his younger brother have been found guilty of plotting to smuggle 200 million Australian dollars ($150 million) worth of cocaine into Australia.

The 45-year-old Baggaley and his 39-year-old brother Dru were charged with attempting to import 650 kilograms (1,430 pounds) of cocaine in 2018. After about eight hours of deliberating, a Brisbane Supreme Court jury found both men guilty on Thursday.

Nathan Baggaley won two canoeing silver medals at the 2004 Athens Olympics and also was a three-time world champion.

But his career was tarnished with drug scandals - testing positive for banned steroids in 2005 and also being jailed with Dru Baggaley 10 years later for his role in a drug manufacturing syndicate.

The Baggaley brothers will be sentenced on a date yet to be decided by the court.