With only three months to go to the Glasgow 2014 Commonwealth Games, Scottish Disability Sport (SDS) said athletes who had been through work capability assessments were finding they could no longer afford to compete or train because of benefit cuts.
The organisation told MSPs its staff and associates from across the country had reported the impact of assessments on the sportsmen and women. Even board members of the governing organisation for disabled sport north of the Border have been affected.
Elite athletes preparing for Glasgow 2014, which runs from July 23 to August 3 and includes five disabled sports, are not thought to be affected. However, sources claim welfare reforms are hitting potential stars at grassroots level. The changes, designed to tighten criteria for sickness and disability benefits, have seen hundreds of thousands of people judged to be fit for work and ineligible for Government support.
But the Department for Work and Pensions (DWP) said it was a "world-leader in support for disabled people", pointing to its role in the Paralympics.
The SDS claim is part of evidence to the Scottish Parliament's Public Petitions Committee and a submission calling for the scrapping of the UK Government's work capability assessor Atos as a Glasgow 2014 key sponsor.
The petition, by the Glasgow Against Atos campaign, has drawn support from the Scottish Trades Union Congress, which said the 2014 Organising Committee had to ask whether it was "satisfied the actions of Atos are compatible with their published values".
The agency, which is leaving its DWP contract, has been the subject of public and political criticism as it administered fit-for-work tests for sick and disabled people as part of the Government's bid to reduce welfare spending. The SDS letter to MSPs states: "The recent welfare reforms have undoubtedly had an impact on those with a disability in Scotland and recently SDS has noticed some athletes and players have been adversely affected by the outcome of work capability assessments.
"The knock-on effect for SDS has been a lack of ability for some athletes and players to contribute to the costs of participating, training or competing in their chosen sport. SDS has no empirical evidence to substantiate this theory, but this is the anecdotal picture that is being fed back to us by our staff, volunteers and key partners."
One senior figure within disabled sport said the problem is "not confined to an isolated one or two individuals" but an increasingly significant issue, adding many athletes associated with SDS have been angry about the Atos sponsorship.
The source said: "There are already huge barriers to participation, not least the cost of accessing facilities."
Ian Hood, of Learning Disability Alliance Scotland, said many people assessed to be able to carry out some work were losing about £40 per week in benefits. He added: "To say because someone can throw a shot put they could pull a lever in a factory is the stuff of the 1870s. Work is more complicated. Having sporting ability doesn't mean you can hold down a full-time job or complete the hours to support yourself."
The STUC said: "We have expressed our concern over the continued involvement of Atos in Glasgow 2014."
A DWP spokesman said: "We're committed to helping disabled people fulfil their potential. That's why we invest heavily in disabled sport, to the tune of £71 million in our professional Summer Paralympic athletes alone."
Glasgow 2014 said Atos had "demonstrated unwavering commitment to driving forward the Olympic and Paralympic movements by providing dedicated practical support to athletes for the last 10 years".
Glasgow Against Atos campaign organiser Sean Clerkin added: "This contribution from SDS validates our petition."