The health scare, which is prevalent in Brazil, is a major concern for organisers and the International Atomic Energy Agency (IAEA) has now been brought in to assist.

The IAEA, a United Nations organisation which promotes the safe and peaceful use of nuclear energy, will ship an "irradiator" device to Brazil once the Government provides the correct permits.

Up to 12 million male Aedes mosquitoes - which spread Zika - will be zapped with the gamma rays to sterilise them.

They will then be released to breed with wild females who will lay eggs which produce no offspring.

The project will be introduced in Juazeiro, a city in the north-east of the country in the state of Bahia, and could then be escalated.

Kostas Bourtzis, a molecular biologist with the IAEA’s insect pest control laboratory, said that the mosquitoes might be released from the air using drones.

"It’s a birth control method, the equivalent of family planning for humans,” he told Reuters.

Gamma rays were previously used to control fruit flies on the Portuguese island Madeira. 

Authorities in Brazil will be desperate to curtail Zika which has sparked panic in some quarters ahead of the Olympics.

The virus - declared a global emergency by the World Health Organization (WHO) - is of particular concern to pregnant women due to a link with microcephaly, which causes babies to be born with small heads and under-developed brains.

However, the WHO has also backed up an International Olympic Committee (IOC) view that the virus will likely be less prevalent when the Games open on August 5 - due to the then cooler conditions in Brazil being less hospitable for the mosquitoes.

Bruce Aylward, WHO’s executive director for outbreaks and health emergencies, also declared that the confined nature of Olympic venues would make it easier for authorities to control any outbreak.

Other effects of Zika include fevers, rashes, joint pain, eye redness and conjunctivitis, although it is thought only 20 per cent of people infected will display any symptoms. 

Advice for athletes includes wearing long sleeve clothing, applying insect repellent, the use of mosquito nets and sleeping in air conditioned rooms.

Uğur Erdener, the Turkish President of World Archery who is a qualified doctor and chair of the IOC's Medical and Scientific Commission, has said he is confident "significant" steps were being taken in Rio.

Nevertheless, athletes have expressed concerns with United States women's football goalkeeper Hope Solo, a double Olympic gold medallist, saying she would not travel in the present climate as she wants to start a family.

Toni Minichiello, the coach of Britain's Olympic heptathlon champion Jessica Ennis-Hill, believes the country should consider moving its pre-Rio training camp, which will be in Belo Horizonte, out of Brazil.

"People finish the Olympics and restart other parts of their life,” said Glenn Merry, chief executive of USRowing, to the Boston Globe.

"Is there a long-term impact to childbearing?

"If not, what’s the medium and short-term impact?

"We want to better educate our athletes so that they can make the decisions they need to make to protect themselves.”