The Queen's golden jubilee in June could result in 10,000 sales of special public liability policies for niche operation Events Insurance Services.
Initial take-up at the Hampshire-based firm had been slow, but it had already received "hundreds" of inquiries about its bespoke product, managing director Lucy Scurlock-Jones said.
Insurance Times last week reported warnings by Zurich Municipal that local authorities could be sued in the event of accidents on their land during street parties and other jubilee celebrations.
Launched last year, the product offers standard cover at levels of £1m, £2m and £5m. Premiums are £52, £80 and £110 respectively.
Cover for £10m costs £370 and the maximum level available is £50m.
The policies are underwritten mainly by UK Insurance.
Scurlock-Jones said: "The main selling point is the public liability.
"We can extend the cover to include fireworks, which would be underwritten at Lloyd's.
"We can cover event property if people are hiring tables, chairs or marquees."
She said her company could also cover employers' liability, for example, if they were hiring waiting staff.
Cancellation cover excludes death of the monarch.
The package is based on similar policies put together for millennium celebrations.
Scurlock-Jones said: "We thought it would start to pick up earlier than this, but since Christmas about one in ten calls is about this one."
The firm has up to 60 confirmed customers. There were reported to be 100,000 street parties for the Queen's silver jubilee in 1977. Based on the same figures, sales to 10% of events would generate 10,000 sales.