The head of Swim Wales, Fergus Feeney, says he “can see the pressure building” as many of the nation’s elite swimmers remain unable to train.
Some of England’s top swimmers are back in training as the UK Government permits elite athletes there to train.
But the Welsh Government has not yet allowed its elite athletes to train again and all swimming pools remain closed.
The issue is due to be discussed at its next lockdown review on 18 June.
“I can see pressure building up if it didn’t happen [then],” said Swim Wales chief executive Feeney.
“There’s a psychological impact in that it potentially sends a message [to our swimmers] that they’re not as important as others.
“The second bit is the physical side. This length of time without swimming is already very unusual. I think it could have a significant effect.
“Anything more than three or four weeks would start to put our swimmers at a disadvantage.”
Feeney maintains he is fully supportive of the Welsh Government’s cautious approach to date.
As it stands, he says, the top swimmers in Wales have ‘no immediate urge’ to get back into a pool.
But their British teammates are also rivals for Olympic and Paralympic places in 2021 and the Commonwealth Games in 2022.
Feeney has warned the Welsh Government a further delay could affect Wales’ future performances at major events.
“We had five Welsh athletes go to Rio [for the Olympics and Paralympics],” he told BBC Sport Wales.
“We brought back a gold [from Aaron Moores] and two silvers [by Jazz Carlin]. So that’s punching far above our weight.
“Unfortunately that return comes at a cost. My fear would be that cost and that consequence is going to be a lack of performance and a lack of medals on the world stage.
“We’re doing our best to make that clear and make sure the Welsh Government know that when they stand on the steps of the Senedd and welcome home these athletes that we’ve got swimmers in amongst them.”
A number of Welsh elite swimmers, including Georgia Davies and Calum Jarvis, are currently based in England so fall under UK Government guidelines where they are based.
But 2018 Commonwealth champion Alys Thomas and two-time Commonwealth medallist Daniel Jervis train in Swansea and have not swum since March.
‘Not our pools to switch on’
Even if the Welsh Government allowed elite swimmers to train again, the next challenge would be getting into a pool.
In England, British Swimming has allowed a small group of top athletes to train in carefully controlled sessions at its National Centres at the University of Bath and Loughborough University.
Swim Wales has two high performance centres in the Wales National Pool in Swansea and Cardiff International Pool.
But both facilities are publicly owned and would ordinarily be used by club athletes, recreational swimmers, learn to swim groups and other aquatic sports.
Discussions are ongoing between the operators and Swim Wales over whether opening purely for a small group of elite athletes is financially viable.
“Having the piece of paper to say you’re permitted to travel and having the vehicle to travel in are two different things,” Feeney continues.
“They’re not our pools to switch on and it’s not just a university or elite environment like some of our counterparts in England.
“It’s got huge financial operating costs.”
But Feeney believes one solution is that his elite swimmers could help trial any new safety protocols leisure facilities plan to introduce in the belief
it could help them work towards a full re-opening to the public when government guidelines allow it.
Swim Wales has also asked the Welsh Government whether certain athletes could be allowed to move to England to train.
But this would require a change in Welsh law and an agreement from British Swimming.
The Welsh Government says First Minster Mark Drakeford has already indicated that developing a return to training protocol for elite athletes would be one of the considerations for the next review on 18 June.
It adds it is currently exploring that potential with Sport Wales.
The chief executive of Sport Wales warned earlier this week that sports need to be patient when planning their return.