Proposed rules for community amateur sports clubs have been published by HM Revenue & Customs after a consultation.
CASCs are not registered charities, but receive many of the same tax reliefs, including the right to claim Gift Aid on donations.
But in its summary of the responses to the consultation, HMRC says that many organisations do not understand or obey the rules, so it is necessary to introduce a clearer regime.
The proposed new rules bring a large number of changes, including for the first time a threshold on participation costs for members of £520. There are also increased thresholds on the amount of money that a club can receive from trading and property, as well as a new threshold for trading with non-members. A rule requiring a club to have no more than 50 per cent non-playing members is retained.
The response says that there appears to be "widespread misunderstanding" about how the existing rules work.
"Some clubs have incorrectly assumed that their CASC status disapplies local licensing laws, Pay As You Earn obligations or immigration requirements," it says.
It adds that it is likely some clubs will have to make changes to comply with the new rules.
"The government has decided to keep the rules as simple as possible so that the smallest volunteer-run clubs will find it easier to comply with the rules," the document says. "This approach means that some clubs may need to change how they are structured if they wish to continue to be a CASC."
Those clubs that do not comply with the new regime will be allowed to deregister without penalty, HMRC has promised.
Thea Longley, a partner in the charity team at the law firm Bates Wells Braithwaite, said that the proposals were "a good compromise" and an improvement on some of the original suggestions from HMRC, which were too restrictive.
"There is a lot still to be decided," she said. "How much detail will HMRC require from clubs to prove that a member is playing or non-playing, for example?"
Longley said she expected the new rules to be in place by the summer, and to be followed by a 12-month grace period to allow clubs time to comply.