Indoor community sport faces "a crisis" unless the government intervenes, the chief executive of Badminton England has warned.
In a letter to the culture secretary, Adrian Christy wrote that thousands of grassroots clubs were "on the brink of losing their facilities" because of Covid-19, and could close.
This would be "catastrophic for the 2.4 million people who play indoor sports regularly", he told Oliver Dowden MP.
"This is more people than play football, rugby and cricket."
He urged the government to protect community sport from "lasting, irrecoverable damage".
Last week indoor gyms, swimming pools and other leisure facilities began to reopen for the first time since March.
They must follow strict hygiene and social distancing measures, such as limiting the number of people using the facility and spacing out equipment, and it is thought almost half have remained shut.
"We are extremely concerned that leisure providers, who are able to reopen their facilities, are having to prioritise the provision of gym activity over community sport," wrote Christy.
"If indoor places to play are lost, vital community activities will bear the brunt of the brutal effect of Covid-19 on sport.
"These are the sports that reach into every community irrespective of age, gender, ethnicity, and physical ability."
This week, the government unveiled a new strategy to tackle obesity.
And Christy added: "Government is right to target healthy living and sport as a key part of the solution; however, this will not work if there are not the indoor spaces for people to play.
"It is crucial, therefore, that further investment in the leisure sector is ring-fenced."
Christy said the issue was exacerbated by the closure of school facilities, where 50% of badminton clubs play.
When asked whether the government was doing enough for community sport on Tuesday, Sports Minister Nigel Huddlestone said, "many sports entities have already taken advantage of measures like furloughing and loans, so support has been given, and Sport England has given out money for emergency cases to the tune of £200m... so a substantial amount of money has been given out".
He added: "I'm talking to colleagues in local government about the importance of getting leisure centres and pools open again.
"They need to open to generate money and get membership fees coming in again so that is a really important stage. Individual councils also have a responsibility here. But they need to open safely."
Swim England chief executive Jane Nickerson has also expressed concern, on Friday tweeting: "Too many pools still closed… Too many clubs can't get back in the water. We need funding."
Financial problems mean less than 20% of pools reopened last weekend.
The cost of heating the pools and implementing the new guidelines, as well as the reduced footfall and fewer swimming lessons, mean many cannot afford to open.
But industry bodies Community Leisure UK and Ukactive estimate leisure centres, swimming pools and community services face a shortfall of more than £800m this year.