File photo shows Jason Day hits his tee shot on the 2nd hole during the third round of the US Open golf tournament at Oakmont Country Club in Pennsylvania, US, on June 18, 2016. [Photo/Agencies]

Australia's world No.1 golfer, Jason Day, has announced he won't be competing in the upcoming Rio Olympics over fears of the Zika virus.

The 28-year-old made the announcement on his social media account on Wednesday morning, stating he would not put his wife and his growing family at risk.

Day joins several of the game's biggest stars in withdrawing from the Games, tarnishing golf's return to the Olympic arena after 112 years.

"It is with deep regret I announce that I will not be competing in the 2016 Summer Olympic Games this coming August in Rio de Janeiro," the Australian said in the statement.

"The reason for my decision is my concerns about the possible transmission of the Zika virus and the potential risks that it may present to my wife's future pregnancies and to future members of our family."

The Zika virus is a mosquito-borne disease which has been linked to severe birth defects for women who are infected with Zika during their pregnancy. The Zika virus began spreading in Brazil during 2015.

As golf returns to the Summer Olympics for the first time since 1904, the sport will now be without two of its biggest drawcards, after world No. 4, Rory McIlroy, withdrew earlier this week from Rio -- also due to Zika virus concerns.

McIlroy and Day join fellow Aussie golfer Marc Leishman, South Africa's Branden Grace, Charl Schwartzel, Louis Oosthuizen and Fiji's Vijay Singh as the other golfers choosing not to attend Rio due to Zika. Australia's Adam Scott and Northern Ireland's Graeme McDowell have withdrawn for undisclosed reasons.

In May this year, 150 health experts sent a letter to the World Health Organisation to postpone the Olympic Games in Rio over the Zika virus concerns. The letter was rejected.

In his statement, Day said that despite his goal to represent Australia in Rio, he would not put his wife Ellie, and their two children in danger.

"While it has always been a major goal to compete in the Olympics on behalf of my country, playing golf cannot take precedent over the safety of our family. I will not place them at risk."

Day said he has informed Australia's coach, Ian Baker Finch, and the CEO of Golf Australia of his decision.

But he has confirmed he will represent Australia at the World Cup in Melbourne in November.