South Africa's Branden Grace has withdrawn from the Rio Olympics due to the ongoing threat of the Zika virus.

The world number 11, who is scheduled to get married later this year, becomes the fourth golfer to pull out of the Games.

Rory McIlroy, Graeme McDowell and Charl Schwartzel also cited concerns over the Zika virus behind their reasoning to opt out of the competition and, with Grace now joining compatriot Schwartzel in withdrawing, South Africa will be without their top three stars in Rio.

"After serious consideration it is with regret that I have decided to withdraw myself from the Olympic competition due to the risk posed by the Zika virus," he said in a statement.

"Although it was a huge goal of mine to represent my country in the Olympics, I am getting married in November and [my partner and I] are hoping to start a family in the near future so I must put the health of my family first.

"I wish the SA team the best of luck in Rio and sincerely apologise to the South African fans as I really appreciate all of the support they give me each week. It would have been a huge honour to represent my country so I really hope to be able to qualify again in four years' time."

This summer's Olympics will be the first time in 112 years that golf has been staged at the quadrennial sporting event.