Music Venue Trust says 90 per cent of music venues and festivals face permanent closure - including The Leadmill, Corporation and Abbeydale Picture House.
The charity wants the government to immediately invest £50m to save them during July, August and September then cut VAT as a longer term support package.
But Music Venue Trust is also concerned about the Prime Minister's 'Build Build Build' announcement which will change planning rules in September.
Developers will be allowed to demolish and rebuild vacant and redundant residential and commercial buildings if they are renovated as homes
A wider range of commercial buildings can also be switched to housing without a planning application.
Mark Davyd, chief executive of Music Venue Trust, said: "Both landlords and tenants need complete clarity from the government that grassroots music venues will continue to be protected assets within the planning framework and that it will not be possible to simply let the businesses occupying them fail and immediately see them converted to residential spaces.
"The Prime Minister's statement contains echoes of the Permitted Development Right which closed hundreds of venues before the government acted to exempt them in 2018.
"The decision to exempt them was taken after a long campaign supported by Boris Johnson as Mayor of London. He was a leading voice to prevent the closure of grassroots music venues.
"The sector needs urgent clarification from the government that it does not intend to change the National Planning Policy Framework and intends to leave the protections for grassroots music venues in place.
"Without that clarification, the statement will have a direct negative impact upon discussions taking place right now between grassroots music venue landlords and tenants."