South African Olympic swimming gold medallist Roland Schoeman has been banned for a year after testing positive for a banned substance last May, governing body FINA said on Thursday.

Schoeman won gold in the 4x100 freestyle relay at the 2004 Athens Games plus individual silver and bronze medals in the 100 and 50m freestyle. He also competed in the 2000, 2008 and 2012 Olympics.

A FINA statement read: "On 18 May 2019, FINA conducted an out-of-competition doping control test on the swimmer Roland Schoeman (RSA). The athlete was tested positive to the substance GW501516 (Class S.4 Hormone and Metabolic Modulators).

"According to the decision of the FINA Doping Panel, Mr. Roland Schoeman has been found to have committed an anti-doping rule violation under FINA DC Rule 2.1 -- presence of prohibited substance in an athlete's sample.

"He has been sanctioned with a twelve (12) months' ineligibility period commencing on 18 May 2019, a date fixed by the Panel pursuant to FINA DC 10.11.1, and ending at the conclusion of 17 May 2020, for his first anti-doping rule violation."

The triple world champion failed to qualify for the 2016 Rio de Janeiro Olympics but said last year he was still hoping to qualify for one more Games.

FINA said Schoeman tested positive for the prohibited substance GW501516 at an out-of-competition control on May 18 last year.