Researchers and commentators are concerned a current in the Olympic Aquatics Centre swimming pool affected the Rio 2016 competition.
Olympic medallist and BBC commentator Andy Jameson posted a link to the research on Twitter and wrote it was "very worrying if true".
Jameson, a 100 metres butterfly bronze medallist at Seoul 1988, wrote: "Very worrying if true! A current circling around the Olympic Pool? Re-swim!
"Crystal Palace pool had it but an Olympic pool definitely should not! Shockingly unfair for those swimming upstream!"
The research, posted on swimswam.com by Barry Revzin, looked at split times per length of the 50 metres pool and used data from the last two World Championships, in Barcelona and Kazan, plus recent United States competitions, for comparison.
Olympic-sized swimming pools are 50m in length and 25m wide, enough room for 10 lanes, although only eight are raced in at a major event.
Research suggests there may have been an issue at the 2013 World Championships and in Rio with assistance from the pool.
"Barcelona and Rio were dramatically different," Revzin wrote.
"In both pools, there was a clear drift from lane one to lane eight - which suggests that swimmers were pushed towards the start end in the upper lanes and pushed towards the turn end in the lower lanes, with the effect greater the further you get from the centre. This is very concerning."
The prospect of drift or a current - caused by the circulation of water from the filtration system - and the difference it makes was starker in the 50m events. At Olympic level the only 50m event is 50m freestyle.
Revzin added: "These results are very disconcerting to me, but do not in and of themselves prove that there is a problem. However, the data strongly points to serious problems in the pool which could have led to an unfair competitive environment, especially in the 50m freestyles. I think it should be investigated."
FINA dismissed the research following consultation with pool manufacturers Myrtha Pools.
Swimming's world governing body said in a statement: "Following recent media reports, FINA has consulted its partner Myrtha Pools and received the reassurance that 'no current was detected in the Olympic Aquatics Stadium pool, at any stage of the competitions' at Rio 2016.
"This reassurance follows on from Myrtha Pools' pre-Games guarantee to FINA that all necessary tests had been successfully carried out, to ensure that the competition environment was completely fair.
"FINA also notes that these comments are exclusively made on the basis of mathematical analysis, without taking into account any scientific evidence in the actual pool constructed for these Games."