At least a third of Britain's community indoor tennis centres could close if they do not receive further financial support from the government, says the Lawn Tennis Association.
The LTA's network of 54 centres has faced a substantial loss of income because of the coronavirus pandemic.
Last week, the government announced a £100m support package for public leisure facilities.
But LTA chief executive Scott Lloyd says more support is needed.
"While we welcome the recent government announcement regarding investment into public leisure, this money will be spread thinly across a huge range of publicly owned sport and leisure facilities," he said.
"Community indoor tennis centres (CITCs) play a pivotal role in supporting the physical and mental health of people in their local communities, but Covid-19 has left many in a perilous position."
Tennis' national governing body said some of its clubs with indoor facilities expect to lose a further £100,000 over the coming weeks because of tier two and three restrictions imposed in some parts of England.
In those areas under such restrictions, able-bodied adults wanting to play indoor tennis can only do so with members of their own household or bubble, or in one-to-one coaching. There is an exemption for disabled players and under-18s.
In Wales, all tennis facilities have closed during the current 'firebreak' lockdown while indoor activities are also limited in Scotland.
"The current restrictions across Britain still mean the number of people who can use these centres is significantly less than in normal circumstances and this will continue to have a huge impact on their financial viability as we move into a difficult winter," Lloyd added.
"As it stands, a large proportion of CITCs still face the very real prospect of closure, which would be catastrophic for tennis players up and down the country.
"We are calling for government to deliver a comprehensive sports recovery fund, which is needed to help protect these facilities and other venues with indoor tennis courts, which we know are facing huge challenges over the coming months."