Speaking in Sao Paulo, Brazilian Equestrian National Federation President Luiz Roberto Giugni accused the Government of delaying the process, and warned it must be completed within the next few weeks.

“If the problem is not resolved by the end of the month, we run the risk of not having the event in Brazil,” he said.

“The situation is complicated … [and] communication with the Ministry is bad.”

Delays are thought to relate to medical issues following the outbreak of several cases of the highly infectious Glanders disease in Brazil, including several close to the proposed venue within the Deodoro venues cluster.

The failure of the Ministry to confirm its final health protocol in time contributed to no international teams competing at August's test event, a three-day eventing competion in which there were ultimately only domestic participants.

A "regionalised zone" was installed around the venue for the test event to protect against contamination.

Officials have refuted Giugni’s claims, however, insisting how  “Brazil is on schedule” and “not at risk of missing deadlines", claiming that its final deadline is 120 days out from the event, which would mean they have until early April to complete their work.

There is a precedent for equestrian events being held outside a host city or nation, with action at the 1956 Games held in Stockholm rather than Melbourne because of Australia's rigorous quarantine regulations, while competition took place in Hong Kong during Beijing 2008.

However, it still appears likely that the protocol will ultimately be approved in time, and Giugni's words appear partly a technique to encourage Brazilian officials to speed-up their progress, a strategy previously used by other Olympic officials when criticising preparations.

It comes at the end of a tough week for Rio in which savings have been announced to many areas of preparations, widely connected to economic problems across Brazil.

In a statement sent to insidethegames, FEI President Ingmar De Vos admitted how the length of the process has had an "important impact" but concluded that they are still looking forward to a "very successful" event in Deodoro.

He is confident the health protocols will be completed "soon".

“We have been working for some time with Rio 2016, the Brazilian and Rio Authorities and the Brazilian Ministry of Agriculture to get the Veterinary Certificate and Protocol approved that will define the conditions for importation and exportation of the horses that will compete at the Rio Olympic Games," he said.

"The process of approval of the equine health certificate by the Brazilian Ministry of Agriculture has already taken a lot of time and is still not finalised.

"This has an important impact as it delays the planning and preparation of the horses that will take part in the Games.

"As the President of the Brazilian Equestrian National Federation, Luiz Robert Giugni has supported us very actively during these negotiations and we appreciate that in his efforts to help the equestrian community in the discussions with his compatriots he is applying all possible pressure to achieve this.

“We have had further discussions earlier this week and I expect the Ministry of Agriculture to issue this certificate very soon so that we can carry on with preparations for the Olympic Games and that the biosecurity protocols will ensure the safe import and export of the Olympic horses.

"Therefore we are confident that our horses will be allowed to travel back and forth to Rio to participate in the 2016 Olympic Games together with all the other Olympic sports.

"We are looking forward to very successful Olympic equestrian events in Deodoro next year.”

In a statement, the IOC also claimed they "are confident that this will be resolved and that the competitions will remain in Deodoro".

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