Among the proposals being discussed was a demand for a return to furlough for cast and crew whose shows are being closed down.
Also affected was the West End’s hottest ticket, Cabaret starring Eddie Redmayne, which was forced to call off performances this week.
Lloyd Webber said the industry faced being “decimated” as the huge surge in Covid cases forced shows to close.
Bookings have also slumped with audiences staying away rather than heading into the West End.
Theatres are still recovering from last year’s lockdown when venues were shut and the effect of the pingdemic which saw shows cancelled at short notice.