Ireland have complained to world rugby chiefs over the selection process for the 2023 World Cup after a controversial technical report gave South Africa the best rating.
The Rugby World Cup Board last week recommended the World Rugby Council award the tournament to South Africa, which the report placed ahead of France and Ireland on an overall score across a range of criteria.
But the publication of the report has proved controversial. Irish officials are unhappy at coming third with a score of 72.25 compared with 75.88 for France and 78.97 for South Africa.
In a letter seen by AFP, Irish Rugby Football Union (IRFU) chief executive Philip Browne outlined Ireland's concerns to the chief executive of World Rugby, Brett Gosper, over stadia, security, hosting of major events and financial commitments and guarantees.
"There are very clear examples in recent times of starkly empty stadia in South Africa for significant fixtures," Browne said in his letter.
"The evaluation report does not appear to address this in any meaningful way," he added.
He also raised the issue of security.
"Was an independently recognised, world-class security organisation used to review the underlying security situation within each bidding country... if not, why not?" he asked.
The letter said: "In our opinion, Ireland's scoring has suffered unreasonably, relative to the scoring for other bidders."
A spokesman for World Rugby, the game's governing body, told AFP that officials would respond directly to the IRFU.
"We stand by the report, which is objective, robust and independently audited," he said.
"Each of the unions, including the candidate unions, were across the process from the very start and agreed to every aspect of it."
The evaluation report also prompted a furious response from Bernard Laporte, president of the French Rugby Federation (FFR), who said the organisation would be writing to World Rugby chairman Bill Beaumont ahead of next week's final vote, seeking a correction over what it said was a series of inaccuracies, including the quality of stadiums and hotels.
Both South Africa, in 1995, and France, in 2007, have previously staged the World Cup outright, while Ireland are bidding to be the main hosts for the first time.
The World Rugby Council will make the final decision in London on November 15.